ID CVE-2018-6594
Summary lib/Crypto/PublicKey/ElGamal.py in PyCrypto through 2.6.1 generates weak ElGamal key parameters, which allows attackers to obtain sensitive information by reading ciphertext data (i.e., it does not have semantic security in face of a ciphertext-only attack). The Decisional Diffie-Hellman (DDH) assumption does not hold for PyCrypto's ElGamal implementation.
References
Vulnerable Configurations
  • Dlitz Pycrypto 2.6.1
    cpe:2.3:a:dlitz:pycrypto:2.6.1
  • Debian Linux 7.0
    cpe:2.3:o:debian:debian_linux:7.0
  • Canonical Ubuntu Linux 12.04 ESM (Extended Security Maintenance)
    cpe:2.3:o:canonical:ubuntu_linux:12.04:-:-:-:esm
  • Canonical Ubuntu Linux 14.04 LTS (Long-Term Support)
    cpe:2.3:o:canonical:ubuntu_linux:14.04:-:-:-:lts
  • Canonical Ubuntu Linux 16.04 LTS (Long-Term Support)
    cpe:2.3:o:canonical:ubuntu_linux:16.04:-:-:-:lts
  • Canonical Ubuntu Linux 17.10
    cpe:2.3:o:canonical:ubuntu_linux:17.10
CVSS
Base: 5.0
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.
nessus via4
  • NASL family PhotonOS Local Security Checks
    NASL id PHOTONOS_PHSA-2018-1_0-0126_PYCRYPTO.NASL
    description An update of the pycrypto package has been released.
    last seen 2019-02-08
    modified 2019-02-07
    plugin id 121827
    published 2019-02-07
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=121827
    title Photon OS 1.0: Pycrypto PHSA-2018-1.0-0126
  • NASL family Amazon Linux Local Security Checks
    NASL id ALA_ALAS-2018-977.NASL
    description Weak ElGamal key parameters in PublicKey/ElGamal.py allow attackers to obtain sensitive information by reading ciphertext : lib/Crypto/PublicKey/ElGamal.py in PyCrypto through 2.6.1 generates weak ElGamal key parameters, which allows attackers to obtain sensitive information by reading ciphertext data (i.e., it does not have semantic security in face of a ciphertext-only attack). The Decisional Diffie-Hellman (DDH) assumption does not hold for PyCrypto's ElGamal implementation. (CVE-2018-6594)
    last seen 2019-02-21
    modified 2018-04-18
    plugin id 108602
    published 2018-03-27
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=108602
    title Amazon Linux AMI : python-crypto (ALAS-2018-977)
  • NASL family Fedora Local Security Checks
    NASL id FEDORA_2018-913C225B49.NASL
    description The textbook ElGamal implementation is not secure. PyCrypto and some other implementations use the wrong algorithm, which may lead to some information disclosure simply by looking at the encrypted text. For a full description, see https://github.com/dlitz/pycrypto/issues/253 This update includes a fix for this problem backported from pycryptodome. 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 2018-03-19
    plugin id 107033
    published 2018-02-28
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=107033
    title Fedora 27 : python-crypto (2018-913c225b49)
  • NASL family Ubuntu Local Security Checks
    NASL id UBUNTU_USN-3616-1.NASL
    description It was discovered that Python Crypto incorrectly generated ElGamal key parameters. A remote attacker could possibly use this issue to obtain sensitive information. 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 108833
    published 2018-04-04
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=108833
    title Ubuntu 14.04 LTS / 16.04 LTS / 17.10 : python-crypto vulnerability (USN-3616-1)
  • NASL family Fedora Local Security Checks
    NASL id FEDORA_2018-0C75CC72BC.NASL
    description The textbook ElGamal implementation is not secure. PyCrypto and some other implementations use the wrong algorithm, which may lead to some information disclosure simply by looking at the encrypted text. For a full description, see https://github.com/dlitz/pycrypto/issues/253 This update includes a fix for this problem backported from pycryptodome. 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 2018-03-19
    plugin id 107155
    published 2018-03-07
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=107155
    title Fedora 26 : python-crypto (2018-0c75cc72bc)
  • NASL family PhotonOS Local Security Checks
    NASL id PHOTONOS_PHSA-2018-2_0-0037.NASL
    description An update of {'mercurial', 'python2', 'zsh', 'pycrypto', 'patch', 'binutils', 'paramiko', 'httpd', 'mysql', 'xerces-c', 'util-linux', 'net-snmp', 'python3', 'sqlite'} packages of Photon OS has been released.
    last seen 2019-02-21
    modified 2019-02-07
    plugin id 111297
    published 2018-07-24
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=111297
    title Photon OS 2.0 : Zsh / Python3 / Xerces / Mercurial / Pmd / Pycrypto / Net / Python2 / Util / Mysql / Paramiko / Binutils / Patch / Sqlite (PhotonOS-PHSA-2018-2.0-0037) (deprecated)
  • NASL family PhotonOS Local Security Checks
    NASL id PHOTONOS_PHSA-2018-1_0-0126.NASL
    description An update of 'paramiko', 'mysql', 'mercurial', 'binutils', 'pycrypto', 'patch', 'sqlite-autoconf', 'httpd', 'python3', 'xerces-c', 'strongswan', 'net-snmp' packages of Photon OS has been released.
    last seen 2019-02-21
    modified 2019-02-07
    plugin id 111930
    published 2018-08-17
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=111930
    title Photon OS 1.0: Binutils / Httpd / Mercurial / Mysql / Net / Paramiko / Patch / Pycrypto / Python3 / Sqlite / Strongswan / Xerces PHSA-2018-1.0-0126 (deprecated)
refmap via4
misc
mlist [debian-lts-announce] 20180215 [SECURITY] [DLA 1283-1] python-crypto security update
ubuntu
  • USN-3616-1
  • USN-3616-2
Last major update 03-02-2018 - 21:29
Published 03-02-2018 - 10:29
Last modified 01-03-2019 - 14:37
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