CVE-2017-3813 in AnyConnect Secure Mobility Client
Summary
by MITRE
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.
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Analysis
by VulDB Data Team • 08/28/2024
The vulnerability identified as CVE-2017-3813 resides within the Start Before Logon (SBL) module of Cisco AnyConnect Secure Mobility Client Software for Windows, representing a critical privilege escalation flaw that undermines fundamental security controls. This vulnerability specifically targets the Windows operating system environment where Cisco AnyConnect is deployed, creating a pathway for local attackers to elevate their privileges from standard user level to SYSTEM level through the manipulation of Internet Explorer processes. The flaw stems from inadequate access control implementation that fails to properly enforce privilege boundaries between different user contexts, allowing unauthorized execution of privileged operations through seemingly benign browser interactions.
The technical exploitation of this vulnerability occurs through a carefully orchestrated sequence where an unauthenticated local attacker leverages the SBL module's improper access control mechanisms to launch Internet Explorer with SYSTEM privileges. This represents a classic privilege escalation vector where the attacker does not need network connectivity or authentication credentials to exploit the flaw, as the vulnerability exists within the local system's privilege management framework. The attacker can simply initiate Internet Explorer through the vulnerable SBL module, which then executes the browser process with elevated privileges, potentially enabling full system compromise. This flaw directly violates the principle of least privilege and demonstrates a critical failure in Windows privilege separation mechanisms.
The operational impact of CVE-2017-3813 extends beyond simple privilege escalation, as it provides attackers with the capability to execute arbitrary commands with SYSTEM-level privileges, effectively granting them complete control over the targeted system. This vulnerability affects Cisco AnyConnect versions prior to 4.4.00243 and 4.3.05017, indicating that organizations running these older versions face significant risk of system compromise. The vulnerability's presence in the SBL module suggests that it may be particularly dangerous in enterprise environments where Cisco AnyConnect is widely deployed for remote access, as it could enable attackers to bypass network security controls and gain persistent access to internal systems. This type of vulnerability aligns with ATT&CK technique T1068 (Local Privilege Escalation) and CWE-276 (Incorrect Default Permissions), demonstrating how insufficient access control implementation can create dangerous attack vectors.
Organizations affected by this vulnerability should immediately implement mitigation strategies including upgrading to Cisco AnyConnect versions 4.4.00243 or later, or 4.3.05017 or later, as these releases contain the necessary patches to address the access control deficiencies. System administrators should also consider implementing additional security controls such as restricting local user access to the SBL module and monitoring for unauthorized Internet Explorer processes running with elevated privileges. The vulnerability's classification under CWE-276 highlights the importance of proper default security configurations and access control enforcement, while its alignment with ATT&CK framework techniques emphasizes the need for comprehensive endpoint security monitoring. Organizations should also conduct thorough vulnerability assessments to identify systems running vulnerable versions and implement layered security approaches to minimize the attack surface exposed by such privilege escalation vulnerabilities.