ID CVE-2016-6210
Summary sshd in OpenSSH before 7.3, when SHA256 or SHA512 are used for user password hashing, uses BLOWFISH hashing on a static password when the username does not exist, which allows remote attackers to enumerate users by leveraging the timing difference between responses when a large password is provided.
References
Vulnerable Configurations
  • OpenBSD OpenSSH 7.2 Patch 2
    cpe:2.3:a:openbsd:openssh:7.2:p2
CVSS
Base: 4.3 (as of 09-03-2017 - 11:20)
Impact:
Exploitability:
CWE CWE-200
CAPEC
  • Subverting Environment Variable Values
    The attacker directly or indirectly modifies environment variables used by or controlling the target software. The attacker's goal is to cause the target software to deviate from its expected operation in a manner that benefits the attacker.
  • Footprinting
    An attacker engages in probing and exploration activity to identify constituents and properties of the target. Footprinting is a general term to describe a variety of information gathering techniques, often used by attackers in preparation for some attack. It consists of using tools to learn as much as possible about the composition, configuration, and security mechanisms of the targeted application, system or network. Information that might be collected during a footprinting effort could include open ports, applications and their versions, network topology, and similar information. While footprinting is not intended to be damaging (although certain activities, such as network scans, can sometimes cause disruptions to vulnerable applications inadvertently) it may often pave the way for more damaging attacks.
  • Exploiting Trust in Client (aka Make the Client Invisible)
    An attack of this type exploits a programs' vulnerabilities in client/server communication channel authentication and data integrity. It leverages the implicit trust a server places in the client, or more importantly, that which the server believes is the client. An attacker executes this type of attack by placing themselves in the communication channel between client and server such that communication directly to the server is possible where the server believes it is communicating only with a valid client. There are numerous variations of this type of attack.
  • Browser Fingerprinting
    An attacker carefully crafts small snippets of Java Script to efficiently detect the type of browser the potential victim is using. Many web-based attacks need prior knowledge of the web browser including the version of browser to ensure successful exploitation of a vulnerability. Having this knowledge allows an attacker to target the victim with attacks that specifically exploit known or zero day weaknesses in the type and version of the browser used by the victim. Automating this process via Java Script as a part of the same delivery system used to exploit the browser is considered more efficient as the attacker can supply a browser fingerprinting method and integrate it with exploit code, all contained in Java Script and in response to the same web page request by the browser.
  • Session Credential Falsification through Prediction
    This attack targets predictable session ID in order to gain privileges. The attacker can predict the session ID used during a transaction to perform spoofing and session hijacking.
  • Reusing Session IDs (aka Session Replay)
    This attack targets the reuse of valid session ID to spoof the target system in order to gain privileges. The attacker tries to reuse a stolen session ID used previously during a transaction to perform spoofing and session hijacking. Another name for this type of attack is Session Replay.
  • Using Slashes in Alternate Encoding
    This attack targets the encoding of the Slash characters. An attacker would try to exploit common filtering problems related to the use of the slashes characters to gain access to resources on the target host. Directory-driven systems, such as file systems and databases, typically use the slash character to indicate traversal between directories or other container components. For murky historical reasons, PCs (and, as a result, Microsoft OSs) choose to use a backslash, whereas the UNIX world typically makes use of the forward slash. The schizophrenic result is that many MS-based systems are required to understand both forms of the slash. This gives the attacker many opportunities to discover and abuse a number of common filtering problems. The goal of this pattern is to discover server software that only applies filters to one version, but not the other.
Access
VectorComplexityAuthentication
NETWORK MEDIUM NONE
Impact
ConfidentialityIntegrityAvailability
PARTIAL NONE NONE
exploit-db via4
  • description OpenSSHD. CVE-2016-6210. Remote exploit for Linux platform
    file exploits/linux/remote/40136.py
    id EDB-ID:40136
    last seen 2016-07-20
    modified 2016-07-20
    platform linux
    port 22
    published 2016-07-20
    reporter 0_o
    source https://www.exploit-db.com/download/40136/
    title OpenSSHD <= 7.2p2 - Username Enumeration
    type remote
  • description OpenSSHD <= 7.2p2 - User Enumeration. CVE-2016-6210. Remote exploit for Linux platform
    file exploits/linux/remote/40113.txt
    id EDB-ID:40113
    last seen 2016-07-18
    modified 2016-07-18
    platform linux
    port 22
    published 2016-07-18
    reporter Eddie Harari
    source https://www.exploit-db.com/download/40113/
    title OpenSSHD <= 7.2p2 - User Enumeration
    type remote
metasploit via4
description This module uses a malformed packet or timing attack to enumerate users on an OpenSSH server. The default action sends a malformed (corrupted) SSH_MSG_USERAUTH_REQUEST packet using public key authentication (must be enabled) to enumerate users. On some versions of OpenSSH under some configurations, OpenSSH will return a "permission denied" error for an invalid user faster than for a valid user, creating an opportunity for a timing attack to enumerate users. Testing note: invalid users were logged, while valid users were not. YMMV.
id MSF:AUXILIARY/SCANNER/SSH/SSH_ENUMUSERS
last seen 2019-03-24
modified 2018-09-15
published 2014-04-28
reliability Normal
reporter Rapid7
source https://github.com/rapid7/metasploit-framework/blob/master/modules/auxiliary/scanner/ssh/ssh_enumusers.rb
title SSH Username Enumeration
nessus via4
  • NASL family FreeBSD Local Security Checks
    NASL id FREEBSD_PKG_ADCCEFD1708011E6A2CBC80AA9043978.NASL
    description The OpenSSH project reports : * sshd(8): Mitigate timing differences in password authentication that could be used to discern valid from invalid account names when long passwords were sent and particular password hashing algorithms are in use on the server. CVE-2016-6210, reported by EddieEzra.Harari at verint.com * sshd(8): (portable only) Ignore PAM environment vars when UseLogin=yes. If PAM is configured to read user-specified environment variables and UseLogin=yes in sshd_config, then a hostile local user may attack /bin/login via LD_PRELOAD or similar environment variables set via PAM. CVE-2015-8325, found by Shayan Sadigh.
    last seen 2019-02-21
    modified 2018-11-10
    plugin id 93267
    published 2016-09-02
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=93267
    title FreeBSD : openssh -- sshd -- remote valid user discovery and PAM /bin/login attack (adccefd1-7080-11e6-a2cb-c80aa9043978)
  • NASL family Slackware Local Security Checks
    NASL id SLACKWARE_SSA_2016-219-03.NASL
    description New openssh packages are available for Slackware 13.0, 13.1, 13.37, 14.0, 14.1, 14.2, and -current to fix security issues.
    last seen 2019-02-21
    modified 2016-10-19
    plugin id 92760
    published 2016-08-08
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=92760
    title Slackware 13.0 / 13.1 / 13.37 / 14.0 / 14.1 / 14.2 / current : openssh (SSA:2016-219-03)
  • NASL family CentOS Local Security Checks
    NASL id CENTOS_RHSA-2017-2029.NASL
    description An update for openssh is now available for Red Hat Enterprise Linux 7. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section. OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server. The following packages have been upgraded to a later upstream version: openssh (7.4p1). (BZ#1341754) Security Fix(es) : * A covert timing channel flaw was found in the way OpenSSH handled authentication of non-existent users. A remote unauthenticated attacker could possibly use this flaw to determine valid user names by measuring the timing of server responses. (CVE-2016-6210) * It was found that OpenSSH did not limit password lengths for password authentication. A remote unauthenticated attacker could use this flaw to temporarily trigger high CPU consumption in sshd by sending long passwords. (CVE-2016-6515) * It was found that ssh-agent could load PKCS#11 modules from arbitrary paths. An attacker having control of the forwarded agent-socket on the server, and the ability to write to the filesystem of the client host, could use this flaw to execute arbitrary code with the privileges of the user running ssh-agent. (CVE-2016-10009) * It was found that the host private key material could possibly leak to the privilege-separated child processes via re-allocated memory. An attacker able to compromise the privilege-separated process could therefore obtain the leaked key information. (CVE-2016-10011) * It was found that the boundary checks in the code implementing support for pre-authentication compression could have been optimized out by certain compilers. An attacker able to compromise the privilege-separated process could possibly use this flaw for further attacks against the privileged monitor process. (CVE-2016-10012) Additional Changes : For detailed information on changes in this release, see the Red Hat Enterprise Linux 7.4 Release Notes linked from the References section.
    last seen 2019-02-21
    modified 2018-11-10
    plugin id 102751
    published 2017-08-25
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=102751
    title CentOS 7 : openssh (CESA-2017:2029)
  • NASL family Misc.
    NASL id OPENSSH_73.NASL
    description According to its banner, the version of OpenSSH running on the remote host is prior to 7.3. It is, therefore, affected by multiple vulnerabilities : - A local privilege escalation when the UseLogin feature is enabled and PAM is configured to read .pam_environment files from home directories. (CVE-2015-8325) - A flaw exists that is due to the program returning shorter response times for authentication requests with overly long passwords for invalid users than for valid users. This may allow a remote attacker to conduct a timing attack and enumerate valid usernames. (CVE-2016-6210) - A denial of service vulnerability exists in the auth_password() function in auth-passwd.c due to a failure to limit password lengths for password authentication. An unauthenticated, remote attacker can exploit this, via a long string, to consume excessive CPU resources, resulting in a denial of service condition. (CVE-2016-6515) - An unspecified flaw exists in the CBC padding oracle countermeasures that allows an unauthenticated, remote attacker to conduct a timing attack. - A flaw exists due to improper operation ordering of MAC verification for Encrypt-then-MAC (EtM) mode transport MAC algorithms when verifying the MAC before decrypting any ciphertext. An unauthenticated, remote attacker can exploit this, via a timing attack, to disclose sensitive information. Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.
    last seen 2019-02-21
    modified 2019-01-02
    plugin id 93194
    published 2016-08-29
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=93194
    title OpenSSH < 7.3 Multiple Vulnerabilities
  • NASL family Oracle Linux Local Security Checks
    NASL id ORACLELINUX_ELSA-2017-2029.NASL
    description From Red Hat Security Advisory 2017:2029 : An update for openssh is now available for Red Hat Enterprise Linux 7. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section. OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server. The following packages have been upgraded to a later upstream version: openssh (7.4p1). (BZ#1341754) Security Fix(es) : * A covert timing channel flaw was found in the way OpenSSH handled authentication of non-existent users. A remote unauthenticated attacker could possibly use this flaw to determine valid user names by measuring the timing of server responses. (CVE-2016-6210) * It was found that OpenSSH did not limit password lengths for password authentication. A remote unauthenticated attacker could use this flaw to temporarily trigger high CPU consumption in sshd by sending long passwords. (CVE-2016-6515) * It was found that ssh-agent could load PKCS#11 modules from arbitrary paths. An attacker having control of the forwarded agent-socket on the server, and the ability to write to the filesystem of the client host, could use this flaw to execute arbitrary code with the privileges of the user running ssh-agent. (CVE-2016-10009) * It was found that the host private key material could possibly leak to the privilege-separated child processes via re-allocated memory. An attacker able to compromise the privilege-separated process could therefore obtain the leaked key information. (CVE-2016-10011) * It was found that the boundary checks in the code implementing support for pre-authentication compression could have been optimized out by certain compilers. An attacker able to compromise the privilege-separated process could possibly use this flaw for further attacks against the privileged monitor process. (CVE-2016-10012) Additional Changes : For detailed information on changes in this release, see the Red Hat Enterprise Linux 7.4 Release Notes linked from the References section.
    last seen 2019-02-21
    modified 2018-09-05
    plugin id 102296
    published 2017-08-09
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=102296
    title Oracle Linux 7 : openssh (ELSA-2017-2029)
  • NASL family CentOS Local Security Checks
    NASL id CENTOS_RHSA-2017-2563.NASL
    description An update for openssh is now available for Red Hat Enterprise Linux 6. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section. OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server. Security Fix(es) : * A covert timing channel flaw was found in the way OpenSSH handled authentication of non-existent users. A remote unauthenticated attacker could possibly use this flaw to determine valid user names by measuring the timing of server responses. (CVE-2016-6210)
    last seen 2019-02-21
    modified 2018-11-10
    plugin id 102885
    published 2017-09-01
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=102885
    title CentOS 6 : openssh (CESA-2017:2563)
  • NASL family Red Hat Local Security Checks
    NASL id REDHAT-RHSA-2017-2029.NASL
    description An update for openssh is now available for Red Hat Enterprise Linux 7. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section. OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server. The following packages have been upgraded to a later upstream version: openssh (7.4p1). (BZ#1341754) Security Fix(es) : * A covert timing channel flaw was found in the way OpenSSH handled authentication of non-existent users. A remote unauthenticated attacker could possibly use this flaw to determine valid user names by measuring the timing of server responses. (CVE-2016-6210) * It was found that OpenSSH did not limit password lengths for password authentication. A remote unauthenticated attacker could use this flaw to temporarily trigger high CPU consumption in sshd by sending long passwords. (CVE-2016-6515) * It was found that ssh-agent could load PKCS#11 modules from arbitrary paths. An attacker having control of the forwarded agent-socket on the server, and the ability to write to the filesystem of the client host, could use this flaw to execute arbitrary code with the privileges of the user running ssh-agent. (CVE-2016-10009) * It was found that the host private key material could possibly leak to the privilege-separated child processes via re-allocated memory. An attacker able to compromise the privilege-separated process could therefore obtain the leaked key information. (CVE-2016-10011) * It was found that the boundary checks in the code implementing support for pre-authentication compression could have been optimized out by certain compilers. An attacker able to compromise the privilege-separated process could possibly use this flaw for further attacks against the privileged monitor process. (CVE-2016-10012) Additional Changes : For detailed information on changes in this release, see the Red Hat Enterprise Linux 7.4 Release Notes linked from the References section.
    last seen 2019-02-21
    modified 2018-11-26
    plugin id 102112
    published 2017-08-02
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=102112
    title RHEL 7 : openssh (RHSA-2017:2029)
  • NASL family F5 Networks Local Security Checks
    NASL id F5_BIGIP_SOL14845276.NASL
    description When SSHD tries to authenticate a non-existing user, it will pick up a fake password structure hard-coded in the SSHD source code. An attacker can measure timing information to determine if a user exists when verifying a password. (CVE-2016-6210)
    last seen 2019-02-21
    modified 2019-01-04
    plugin id 96106
    published 2016-12-27
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=96106
    title F5 Networks BIG-IP : OpenSSH vulnerability (K14845276)
  • NASL family Oracle Linux Local Security Checks
    NASL id ORACLELINUX_ELSA-2017-2563.NASL
    description From Red Hat Security Advisory 2017:2563 : An update for openssh is now available for Red Hat Enterprise Linux 6. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section. OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server. Security Fix(es) : * A covert timing channel flaw was found in the way OpenSSH handled authentication of non-existent users. A remote unauthenticated attacker could possibly use this flaw to determine valid user names by measuring the timing of server responses. (CVE-2016-6210)
    last seen 2019-02-21
    modified 2018-07-25
    plugin id 102904
    published 2017-09-01
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=102904
    title Oracle Linux 6 : openssh (ELSA-2017-2563)
  • NASL family Debian Local Security Checks
    NASL id DEBIAN_DLA-578.NASL
    description OpenSSH secure shell client and server had a user enumeration problem reported. CVE-2016-6210 User enumeration via covert timing channel For Debian 7 'Wheezy', this problem has been fixed in version 6.0p1-4+deb7u5. We recommend that you upgrade your openssh packages. NOTE: Tenable Network Security has extracted the preceding description block directly from the DLA security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen 2019-02-21
    modified 2018-07-09
    plugin id 92641
    published 2016-08-01
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=92641
    title Debian DLA-578-1 : openssh security update
  • NASL family Amazon Linux Local Security Checks
    NASL id ALA_ALAS-2017-898.NASL
    description A covert timing channel flaw was found in the way OpenSSH handled authentication of non-existent users. A remote unauthenticated attacker could possibly use this flaw to determine valid user names by measuring the timing of server responses. (CVE-2016-6210) It was found that OpenSSH did not limit password lengths for password authentication. A remote unauthenticated attacker could use this flaw to temporarily trigger high CPU consumption in sshd by sending long passwords. (CVE-2016-6515) It was found that ssh-agent could load PKCS#11 modules from arbitrary paths. An attacker having control of the forwarded agent-socket on the server, and the ability to write to the filesystem of the client host, could use this flaw to execute arbitrary code with the privileges of the user running ssh-agent. (CVE-2016-10009) It was found that the host private key material could possibly leak to the privilege-separated child processes via re-allocated memory. An attacker able to compromise the privilege-separated process could therefore obtain the leaked key information. (CVE-2016-10011) It was found that the boundary checks in the code implementing support for pre-authentication compression could have been optimized out by certain compilers. An attacker able to compromise the privilege-separated process could possibly use this flaw for further attacks against the privileged monitor process. (CVE-2016-10012)
    last seen 2019-02-21
    modified 2018-04-18
    plugin id 103650
    published 2017-10-04
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=103650
    title Amazon Linux AMI : openssh (ALAS-2017-898)
  • NASL family Debian Local Security Checks
    NASL id DEBIAN_DSA-3626.NASL
    description Eddie Harari reported that the OpenSSH SSH daemon allows user enumeration through timing differences when trying to authenticate users. When sshd tries to authenticate a non-existing user, it will pick up a fixed fake password structure with a hash based on the Blowfish algorithm. If real users passwords are hashed using SHA256/SHA512, then a remote attacker can take advantage of this flaw by sending large passwords, receiving shorter response times from the server for non-existing users.
    last seen 2019-02-21
    modified 2018-11-10
    plugin id 92526
    published 2016-07-25
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=92526
    title Debian DSA-3626-1 : openssh - security update
  • NASL family SuSE Local Security Checks
    NASL id OPENSUSE-2016-1096.NASL
    description This update for openssh fixes the following issues : - Prevent user enumeration through the timing of password processing (bsc#989363, CVE-2016-6210) - Allow lowering the DH groups parameter limit in server as well as when GSSAPI key exchange is used (bsc#948902) - limit accepted password length (prevents possible DoS) (bsc#992533, CVE-2016-6515) Bug fixes : - avoid complaining about unset DISPLAY variable (bsc#981654) This update was imported from the SUSE:SLE-12:Update update project.
    last seen 2019-02-21
    modified 2016-10-13
    plugin id 93598
    published 2016-09-20
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=93598
    title openSUSE Security Update : openssh (openSUSE-2016-1096)
  • NASL family Fedora Local Security Checks
    NASL id FEDORA_2016-7440FA5CE2.NASL
    description Security fix for CVE-2016-6210 Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen 2019-02-21
    modified 2017-03-14
    plugin id 92476
    published 2016-07-21
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=92476
    title Fedora 24 : openssh (2016-7440fa5ce2)
  • NASL family SuSE Local Security Checks
    NASL id SUSE_SU-2016-2388-1.NASL
    description This update for OpenSSH fixes the following issues : - Prevent user enumeration through the timing of password processing. (bsc#989363, CVE-2016-6210) - Allow lowering the DH groups parameter limit in server as well as when GSSAPI key exchange is used. (bsc#948902) - Sanitize input for xauth(1). (bsc#970632, CVE-2016-3115) - Prevent X11 SECURITY circumvention when forwarding X11 connections. (bsc#962313, CVE-2016-1908) - Disable DH parameters under 2048 bits by default and allow lowering the limit back to the RFC 4419 specified minimum through an option. (bsc#932483, bsc#948902) - Ignore PAM environment when using login. (bsc#975865, CVE-2015-8325) - Limit the accepted password length (prevents a possible denial of service). (bsc#992533, CVE-2016-6515) - Relax version requires for the openssh-askpass sub-package. (bsc#962794) - Avoid complaining about unset DISPLAY variable. (bsc#981654) - Initialize message id to prevent connection breakups in some cases. (bsc#959096) Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen 2019-02-21
    modified 2018-11-29
    plugin id 93735
    published 2016-09-27
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=93735
    title SUSE SLES11 Security Update : openssh (SUSE-SU-2016:2388-1)
  • NASL family Ubuntu Local Security Checks
    NASL id UBUNTU_USN-3061-1.NASL
    description Eddie Harari discovered that OpenSSH incorrectly handled password hashing when authenticating non-existing users. A remote attacker could perform a timing attack and enumerate valid users. (CVE-2016-6210) Tomas Kuthan, Andres Rojas, and Javier Nieto discovered that OpenSSH did not limit password lengths. A remote attacker could use this issue to cause OpenSSH to consume resources, leading to a denial of service. (CVE-2016-6515). Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen 2019-02-21
    modified 2018-12-01
    plugin id 92985
    published 2016-08-16
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=92985
    title Ubuntu 12.04 LTS / 14.04 LTS / 16.04 LTS : openssh vulnerabilities (USN-3061-1)
  • NASL family Scientific Linux Local Security Checks
    NASL id SL_20170801_OPENSSH_ON_SL7_X.NASL
    description The following packages have been upgraded to a later upstream version: openssh (7.4p1). Security Fix(es) : - A covert timing channel flaw was found in the way OpenSSH handled authentication of non-existent users. A remote unauthenticated attacker could possibly use this flaw to determine valid user names by measuring the timing of server responses. (CVE-2016-6210) - It was found that OpenSSH did not limit password lengths for password authentication. A remote unauthenticated attacker could use this flaw to temporarily trigger high CPU consumption in sshd by sending long passwords. (CVE-2016-6515) - It was found that ssh-agent could load PKCS#11 modules from arbitrary paths. An attacker having control of the forwarded agent-socket on the server, and the ability to write to the filesystem of the client host, could use this flaw to execute arbitrary code with the privileges of the user running ssh-agent. (CVE-2016-10009) - It was found that the host private key material could possibly leak to the privilege-separated child processes via re-allocated memory. An attacker able to compromise the privilege-separated process could therefore obtain the leaked key information. (CVE-2016-10011) - It was found that the boundary checks in the code implementing support for pre-authentication compression could have been optimized out by certain compilers. An attacker able to compromise the privilege-separated process could possibly use this flaw for further attacks against the privileged monitor process. (CVE-2016-10012)
    last seen 2019-02-21
    modified 2018-12-27
    plugin id 102650
    published 2017-08-22
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=102650
    title Scientific Linux Security Update : openssh on SL7.x x86_64
  • NASL family OracleVM Local Security Checks
    NASL id ORACLEVM_OVMSA-2017-0150.NASL
    description The remote OracleVM system is missing necessary patches to address critical security updates : - Fix for CVE-2016-6210: User enumeration via covert timing channel (#1357442)
    last seen 2019-02-21
    modified 2018-07-25
    plugin id 102908
    published 2017-09-01
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=102908
    title OracleVM 3.3 / 3.4 : openssh (OVMSA-2017-0150)
  • NASL family Huawei Local Security Checks
    NASL id EULEROS_SA-2017-1190.NASL
    description According to the version of the openssh packages installed, the EulerOS installation on the remote host is affected by the following vulnerability : - A covert timing channel flaw was found in the way OpenSSH handled authentication of non-existent users. A remote unauthenticated attacker could possibly use this flaw to determine valid user names by measuring the timing of server responses. (CVE-2016-6210) Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen 2019-02-21
    modified 2018-11-14
    plugin id 103028
    published 2017-09-08
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=103028
    title EulerOS 2.0 SP2 : openssh (EulerOS-SA-2017-1190)
  • NASL family Red Hat Local Security Checks
    NASL id REDHAT-RHSA-2017-2563.NASL
    description An update for openssh is now available for Red Hat Enterprise Linux 6. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section. OpenSSH is an SSH protocol implementation supported by a number of Linux, UNIX, and similar operating systems. It includes the core files necessary for both the OpenSSH client and server. Security Fix(es) : * A covert timing channel flaw was found in the way OpenSSH handled authentication of non-existent users. A remote unauthenticated attacker could possibly use this flaw to determine valid user names by measuring the timing of server responses. (CVE-2016-6210)
    last seen 2019-02-21
    modified 2018-11-10
    plugin id 102909
    published 2017-09-01
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=102909
    title RHEL 6 : openssh (RHSA-2017:2563)
  • NASL family SuSE Local Security Checks
    NASL id SUSE_SU-2016-2280-1.NASL
    description This update for openssh fixes the following issues : - Prevent user enumeration through the timing of password processing (bsc#989363, CVE-2016-6210) [-prevent_timing_user_enumeration] - Allow lowering the DH groups parameter limit in server as well as when GSSAPI key exchange is used (bsc#948902) - limit accepted password length (prevents possible DoS) (bsc#992533, CVE-2016-6515) Bug fixes : - avoid complaining about unset DISPLAY variable (bsc#981654) Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen 2019-02-21
    modified 2018-11-29
    plugin id 93455
    published 2016-09-13
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=93455
    title SUSE SLED12 / SLES12 Security Update : openssh (SUSE-SU-2016:2280-1)
  • NASL family AIX Local Security Checks
    NASL id AIX_OPENSSH_ADVISORY9.NASL
    description The remote AIX host has a version of OpenSSH installed that is affected by the following vulnerabilities : - An elevation of privilege vulnerability exists in the do_setup_env() function within file session.c when handling user-supplied environmental variables. A local attacker can exploit this to gain elevated privileges by triggering a crafted environment for the /bin/login program. This vulnerability requires that the UseLogin feature is enabled and that PAM is configured to read .pam_environment files in user home directories. (CVE-2015-8325) - A flaw exists when handling authentication requests that involve overly long passwords due to returning shorter response times for requests for invalid users than for valid users. An unauthenticated, remote attacker can exploit this to enumerate valid usernames by conducting a timing attack. (CVE-2016-6210) - A denial of service vulnerability exists in the auth_password() function within auth-passwd.c due to a a failure to limit password lengths. An unauthenticated, remote attacker can exploit this, via overly long passwords, to cause the excessive consumption of CPU resources. (CVE-2016-6515)
    last seen 2019-02-21
    modified 2018-06-29
    plugin id 95477
    published 2016-12-02
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=95477
    title AIX OpenSSH Advisory : openssh_advisory9.asc
  • NASL family Gentoo Local Security Checks
    NASL id GENTOO_GLSA-201612-18.NASL
    description The remote host is affected by the vulnerability described in GLSA-201612-18 (OpenSSH: Multiple vulnerabilities) Multiple vulnerabilities have been discovered in OpenSSH. Please review the CVE identifiers referenced below for details. Impact : Remote attackers could cause Denial of Service and conduct user enumeration. Workaround : There is no known workaround at this time.
    last seen 2019-02-21
    modified 2018-01-26
    plugin id 95604
    published 2016-12-07
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=95604
    title GLSA-201612-18 : OpenSSH: Multiple vulnerabilities
  • NASL family SuSE Local Security Checks
    NASL id SUSE_SU-2016-2281-1.NASL
    description This update for openssh fixes the following issues : - CVE-2016-6210: Prevent user enumeration through the timing of password processing (bsc#989363) [-prevent_timing_user_enumeration] - Allow lowering the DH groups parameter limit in server as well as when GSSAPI key exchange is used (bsc#948902) - CVE-2016-6515: Limiting the accepted password length to prevent possible DoS (bsc#992533) Bug fixes : - avoid complaining about unset DISPLAY variable (bsc#981654) Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen 2019-02-21
    modified 2018-11-29
    plugin id 93456
    published 2016-09-13
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=93456
    title SUSE SLES11 Security Update : openssh (SUSE-SU-2016:2281-1)
  • NASL family Huawei Local Security Checks
    NASL id EULEROS_SA-2017-1189.NASL
    description According to the version of the openssh packages installed, the EulerOS installation on the remote host is affected by the following vulnerability : - A covert timing channel flaw was found in the way OpenSSH handled authentication of non-existent users. A remote unauthenticated attacker could possibly use this flaw to determine valid user names by measuring the timing of server responses. (CVE-2016-6210) Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen 2019-02-21
    modified 2018-11-14
    plugin id 103027
    published 2017-09-08
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=103027
    title EulerOS 2.0 SP1 : openssh (EulerOS-SA-2017-1189)
packetstorm via4
redhat via4
advisories
  • bugzilla
    id 1357442
    title CVE-2016-6210 openssh: User enumeration via covert timing channel
    oval
    AND
    • OR
      • comment Red Hat Enterprise Linux 6 Client is installed
        oval oval:com.redhat.rhsa:tst:20100842001
      • comment Red Hat Enterprise Linux 6 Server is installed
        oval oval:com.redhat.rhsa:tst:20100842002
      • comment Red Hat Enterprise Linux 6 Workstation is installed
        oval oval:com.redhat.rhsa:tst:20100842003
      • comment Red Hat Enterprise Linux 6 ComputeNode is installed
        oval oval:com.redhat.rhsa:tst:20100842004
    • OR
      • AND
        • comment openssh is earlier than 0:5.3p1-123.el6_9
          oval oval:com.redhat.rhsa:tst:20172563015
        • comment openssh is signed with Red Hat redhatrelease2 key
          oval oval:com.redhat.rhsa:tst:20120884006
      • AND
        • comment openssh-askpass is earlier than 0:5.3p1-123.el6_9
          oval oval:com.redhat.rhsa:tst:20172563011
        • comment openssh-askpass is signed with Red Hat redhatrelease2 key
          oval oval:com.redhat.rhsa:tst:20120884008
      • AND
        • comment openssh-clients is earlier than 0:5.3p1-123.el6_9
          oval oval:com.redhat.rhsa:tst:20172563005
        • comment openssh-clients is signed with Red Hat redhatrelease2 key
          oval oval:com.redhat.rhsa:tst:20120884014
      • AND
        • comment openssh-ldap is earlier than 0:5.3p1-123.el6_9
          oval oval:com.redhat.rhsa:tst:20172563007
        • comment openssh-ldap is signed with Red Hat redhatrelease2 key
          oval oval:com.redhat.rhsa:tst:20120884012
      • AND
        • comment openssh-server is earlier than 0:5.3p1-123.el6_9
          oval oval:com.redhat.rhsa:tst:20172563009
        • comment openssh-server is signed with Red Hat redhatrelease2 key
          oval oval:com.redhat.rhsa:tst:20120884016
      • AND
        • comment pam_ssh_agent_auth is earlier than 0:0.9.3-123.el6_9
          oval oval:com.redhat.rhsa:tst:20172563013
        • comment pam_ssh_agent_auth is signed with Red Hat redhatrelease2 key
          oval oval:com.redhat.rhsa:tst:20120884010
    rhsa
    id RHSA-2017:2563
    released 2017-08-31
    severity Moderate
    title RHSA-2017:2563: openssh security update (Moderate)
  • rhsa
    id RHSA-2017:2029
rpms
  • openssh-0:7.4p1-11.el7
  • openssh-askpass-0:7.4p1-11.el7
  • openssh-cavs-0:7.4p1-11.el7
  • openssh-clients-0:7.4p1-11.el7
  • openssh-keycat-0:7.4p1-11.el7
  • openssh-ldap-0:7.4p1-11.el7
  • openssh-server-0:7.4p1-11.el7
  • openssh-server-sysvinit-0:7.4p1-11.el7
  • pam_ssh_agent_auth-0:0.10.3-1.11.el7
  • openssh-0:5.3p1-123.el6_9
  • openssh-askpass-0:5.3p1-123.el6_9
  • openssh-clients-0:5.3p1-123.el6_9
  • openssh-ldap-0:5.3p1-123.el6_9
  • openssh-server-0:5.3p1-123.el6_9
  • pam_ssh_agent_auth-0:0.9.3-123.el6_9
refmap via4
bid 91812
confirm
debian DSA-3626
exploit-db
  • 40113
  • 40136
fulldisc 20160714 opensshd - user enumeration
gentoo GLSA-201612-18
sectrack 1036319
Last major update 09-03-2017 - 11:51
Published 13-02-2017 - 12:59
Last modified 07-02-2019 - 06:29
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