CVE-2016-9100 in Advanced Secure Gateway
Summary
by MITRE
Symantec Advanced Secure Gateway (ASG) 6.6 prior to 6.6.5.13, ASG 6.7 prior to 6.7.3.1, ProxySG 6.5 prior to 6.5.10.6, ProxySG 6.6 prior to 6.6.5.13, and ProxySG 6.7 prior to 6.7.3.1 are susceptible to an information disclosure vulnerability. An attacker with local access to the client host of an authenticated administrator user can, under certain circumstances, obtain sensitive authentication credential information.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 01/30/2021
The vulnerability identified as CVE-2016-9100 represents a critical information disclosure flaw affecting Symantec Advanced Secure Gateway and ProxySG products across multiple versions. This vulnerability specifically targets the authentication mechanisms of these security appliances, creating a pathway for attackers to potentially compromise administrator credentials. The flaw manifests when an attacker possesses local access to a client host that is authenticated to the system, allowing them to exploit conditions that result in credential exposure. The affected versions include ASG 6.6 prior to 6.6.5.13, ASG 6.7 prior to 6.7.3.1, ProxySG 6.5 prior to 6.5.10.6, ProxySG 6.6 prior to 6.6.5.13, and ProxySG 6.7 prior to 6.7.3.1, indicating a widespread impact across Symantec's secure gateway product line. This vulnerability falls under the CWE-200 category of "Information Exposure" and aligns with ATT&CK technique T1078 which covers legitimate credentials and valid accounts as a means of gaining access to systems.
The technical implementation of this vulnerability stems from insufficient validation of authentication contexts when local access is present on client hosts. When an authenticated administrator session exists on a compromised client machine, the system fails to properly enforce security boundaries that would normally prevent credential leakage. This flaw essentially allows for a privilege escalation scenario where local compromise can lead to broader authentication information disclosure. The vulnerability exploits the trust relationship between client hosts and the authentication system, creating an attack vector that bypasses normal security controls. Attackers leveraging this vulnerability can potentially extract session tokens, authentication keys, or other sensitive credential information that would normally be protected within the secure gateway environment.
The operational impact of CVE-2016-9100 extends beyond simple credential theft, as it represents a fundamental breakdown in the security architecture of these appliances. Organizations using affected Symantec products face potential unauthorized access to their secure network infrastructure, as compromised administrator credentials could provide attackers with elevated privileges and access to sensitive network resources. The vulnerability creates a scenario where physical access or local compromise of a client host can result in remote credential exposure, making it particularly dangerous for environments where physical security controls may be insufficient. This information disclosure could enable attackers to perform administrative functions, modify security policies, or access protected network segments that would normally require proper authentication.
Organizations should implement immediate mitigations including applying the vendor patches released for versions 6.6.5.13, 6.7.3.1, and 6.5.10.6, which address the authentication context validation issues. Network segmentation and access controls should be enhanced to limit local access to client hosts that may interact with secure gateway appliances. Monitoring for unauthorized local access attempts and anomalous authentication patterns should be implemented to detect potential exploitation of this vulnerability. Security teams should also review and strengthen credential management practices, including regular credential rotation and multi-factor authentication implementation where possible. The vulnerability demonstrates the importance of maintaining up-to-date security patches and the potential risks associated with local access compromises in enterprise security infrastructure, particularly in environments where security appliances serve as critical network defense mechanisms.