ID CVE-2017-3813
Summary A vulnerability in the Start Before Logon (SBL) module of Cisco AnyConnect Secure Mobility Client Software for Windows could allow an unauthenticated, local attacker to open Internet Explorer with the privileges of the SYSTEM user. The vulnerability is due to insufficient implementation of the access controls. An attacker could exploit this vulnerability by opening the Internet Explorer browser. An exploit could allow the attacker to use Internet Explorer with the privileges of the SYSTEM user. This may allow the attacker to execute privileged commands on the targeted system. This vulnerability affects versions prior to released versions 4.4.00243 and later and 4.3.05017 and later. Cisco Bug IDs: CSCvc43976.
References
Vulnerable Configurations
  • Cisco AnyConnect Secure Mobility Client 4.0.00052
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.0.00052
  • Cisco AnyConnect Secure Mobility Client 4.0.00061
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.0.00061
  • Cisco AnyConnect Secure Mobility Client 4.1.00028
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.1.00028
  • Cisco AnyConnect Secure Mobility Client 4.1.02011
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.1.02011
  • Cisco AnyConnect Secure Mobility Client 4.1.04011
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.1.04011
  • Cisco AnyConnect Secure Mobility Client 4.1.06013
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.1.06013
  • Cisco AnyConnect Secure Mobility Client 4.1.06020
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.1.06020
  • Cisco AnyConnect Secure Mobility Client 4.1.08005
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.1.08005
  • cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.2.04039
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.2.04039
  • Cisco AnyConnect Secure Mobility Client 4.2.00096
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.2.00096
  • Cisco AnyConnect Secure Mobility Client 4.2.01022
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.2.01022
  • Cisco AnyConnect Secure Mobility Client 4.2.01035
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.2.01035
  • Cisco AnyConnect Secure Mobility Client 4.2.02075
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.2.02075
  • Cisco AnyConnect Secure Mobility Client 4.2.03013
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.2.03013
  • Cisco AnyConnect Secure Mobility Client 4.2.04018
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.2.04018
  • Cisco AnyConnect Secure Mobility Client 4.2.05015
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.2.05015
  • Cisco AnyConnect Secure Mobility Client 4.2.06014
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.2.06014
  • cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.3.00748
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.3.00748
  • cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.3.01095
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.3.01095
  • Cisco AnyConnect Secure Mobility Client 4.3.02039
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.3.02039
  • Cisco AnyConnect Secure Mobility Client 4.3.03086
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.3.03086
  • Cisco AnyConnect Secure Mobility Client 4.3.04027
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.3.04027
  • cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.0.00051
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.0.00051
  • Cisco AnyConnect Secure Mobility Client 4.0.00057
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.0.00057
  • cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.0.00048
    cpe:2.3:a:cisco:anyconnect_secure_mobility_client:4.0.00048
CVSS
Base: 7.2 (as of 24-02-2017 - 09:59)
Impact:
Exploitability:
CWE CWE-264
CAPEC
  • Accessing, Modifying or Executing Executable Files
    An attack of this type exploits a system's configuration that allows an attacker to either directly access an executable file, for example through shell access; or in a possible worst case allows an attacker to upload a file and then execute it. Web servers, ftp servers, and message oriented middleware systems which have many integration points are particularly vulnerable, because both the programmers and the administrators must be in synch regarding the interfaces and the correct privileges for each interface.
  • Leverage Executable Code in Non-Executable Files
    An attack of this type exploits a system's trust in configuration and resource files, when the executable loads the resource (such as an image file or configuration file) the attacker has modified the file to either execute malicious code directly or manipulate the target process (e.g. application server) to execute based on the malicious configuration parameters. Since systems are increasingly interrelated mashing up resources from local and remote sources the possibility of this attack occurring is high. The attack can be directed at a client system, such as causing buffer overrun through loading seemingly benign image files, as in Microsoft Security Bulletin MS04-028 where specially crafted JPEG files could cause a buffer overrun once loaded into the browser. Another example targets clients reading pdf files. In this case the attacker simply appends javascript to the end of a legitimate url for a pdf (http://www.gnucitizen.org/blog/danger-danger-danger/) http://path/to/pdf/file.pdf#whatever_name_you_want=javascript:your_code_here The client assumes that they are reading a pdf, but the attacker has modified the resource and loaded executable javascript into the client's browser process. The attack can also target server processes. The attacker edits the resource or configuration file, for example a web.xml file used to configure security permissions for a J2EE app server, adding role name "public" grants all users with the public role the ability to use the administration functionality. The server trusts its configuration file to be correct, but when they are manipulated, the attacker gains full control.
  • Blue Boxing
    This type of attack against older telephone switches and trunks has been around for decades. A tone is sent by an adversary to impersonate a supervisor signal which has the effect of rerouting or usurping command of the line. While the US infrastructure proper may not contain widespread vulnerabilities to this type of attack, many companies are connected globally through call centers and business process outsourcing. These international systems may be operated in countries which have not upgraded Telco infrastructure and so are vulnerable to Blue boxing. Blue boxing is a result of failure on the part of the system to enforce strong authorization for administrative functions. While the infrastructure is different than standard current applications like web applications, there are historical lessons to be learned to upgrade the access control for administrative functions.
  • Restful Privilege Elevation
    Rest uses standard HTTP (Get, Put, Delete) style permissions methods, but these are not necessarily correlated generally with back end programs. Strict interpretation of HTTP get methods means that these HTTP Get services should not be used to delete information on the server, but there is no access control mechanism to back up this logic. This means that unless the services are properly ACL'd and the application's service implementation are following these guidelines then an HTTP request can easily execute a delete or update on the server side. The attacker identifies a HTTP Get URL such as http://victimsite/updateOrder, which calls out to a program to update orders on a database or other resource. The URL is not idempotent so the request can be submitted multiple times by the attacker, additionally, the attacker may be able to exploit the URL published as a Get method that actually performs updates (instead of merely retrieving data). This may result in malicious or inadvertent altering of data on the server.
  • Target Programs with Elevated Privileges
    This attack targets programs running with elevated privileges. The attacker would try to leverage a bug in the running program and get arbitrary code to execute with elevated privileges. For instance an attacker would look for programs that write to the system directories or registry keys (such as HKLM, which stores a number of critical Windows environment variables). These programs are typically running with elevated privileges and have usually not been designed with security in mind. Such programs are excellent exploit targets because they yield lots of power when they break. The malicious user try to execute its code at the same level as a privileged system call.
  • Manipulating Input to File System Calls
    An attacker manipulates inputs to the target software which the target software passes to file system calls in the OS. The goal is to gain access to, and perhaps modify, areas of the file system that the target software did not intend to be accessible.
Access
VectorComplexityAuthentication
LOCAL LOW NONE
Impact
ConfidentialityIntegrityAvailability
COMPLETE COMPLETE COMPLETE
exploit-db via4
description Cisco AnyConnect Secure Mobility Client 4.3.04027 - Privilege Escalation. CVE-2017-3813. Local exploit for Windows platform
file exploits/windows/local/41476.txt
id EDB-ID:41476
last seen 2017-02-28
modified 2017-02-28
platform windows
port
published 2017-02-28
reporter Exploit-DB
source https://www.exploit-db.com/download/41476/
title Cisco AnyConnect Secure Mobility Client 4.3.04027 - Privilege Escalation
type local
nessus via4
NASL family Windows
NASL id CISCO_ANYCONNECT_CSCVC43976.NASL
description The version of Cisco AnyConnect Secure Mobility Client installed on the remote Windows host is 4.0.x prior to 4.3.05017 or 4.4.x prior to 4.4.00243. It is, therefore, affected by a privilege escalation vulnerability in the Start Before Logon (SBL) module due to insufficient access controls. A local attacker can exploit this to open Internet Explorer with SYSTEM level privileges. Note that the SBL module is not installed by default.
last seen 2018-09-01
modified 2018-07-09
plugin id 97226
published 2017-02-17
reporter Tenable
source https://www.tenable.com/plugins/index.php?view=single&id=97226
title Cisco AnyConnect Secure Mobility Client 4.0.x < 4.3.05017 / 4.4.x < 4.4.00243 SBL Module Privilege Escalation
packetstorm via4
data source https://packetstormsecurity.com/files/download/141394/ciscoanyconnectsbl-escalate.txt
id PACKETSTORM:141394
last seen 2017-03-02
published 2017-03-02
reporter Pcchillin
source https://packetstormsecurity.com/files/141394/Cisco-AnyConnect-SBL-4.3.04027-Local-Privilege-Escalation.html
title Cisco AnyConnect SBL 4.3.04027 Local Privilege Escalation
refmap via4
bid 96145
confirm https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170208-anyconnect
sectrack 1037796
Last major update 15-03-2017 - 21:59
Published 09-02-2017 - 12:59
Last modified 24-07-2017 - 21:29
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