CVE-2016-1411 in Email Security Appliance
Summary
by MITRE
A vulnerability in the update functionality of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA), Cisco Web Security Appliance (WSA), and Cisco Content Management Security Appliance (SMA) could allow an unauthenticated, remote attacker to impersonate the update server. More Information: CSCul88715, CSCul94617, CSCul94627. Known Affected Releases: 7.5.2-201 7.6.3-025 8.0.1-023 8.5.0-000 8.5.0-ER1-198 7.5.2-HP2-303 7.7.0-608 7.7.5-835 8.5.1-021 8.8.0-000 7.9.1-102 8.0.0-404 8.1.1-013 8.2.0-222. Known Fixed Releases: 8.0.2-069 8.0.2-074 8.5.7-042 9.1.0-032 8.5.2-027 9.6.1-019.
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Analysis
by VulDB Data Team • 07/05/2019
This vulnerability resides within the update mechanism of Cisco's email, web, and content security appliances, specifically affecting AsyncOS software versions across multiple product lines. The flaw represents a critical authentication bypass that allows remote attackers to masquerade as legitimate update servers without requiring any credentials or prior access to the system. The vulnerability stems from insufficient validation of update server authenticity during the software update process, creating a pathway for malicious actors to inject unauthorized updates or manipulate the update workflow.
The technical implementation of this vulnerability involves a weakness in the cryptographic verification process used by the security appliances to authenticate update sources. Attackers can exploit this by intercepting update communications and presenting forged update server certificates or by manipulating the update protocol to redirect update requests to malicious servers. This weakness directly maps to CWE-310, which covers cryptographic issues related to authentication and key management. The vulnerability enables a range of malicious activities including but not limited to the deployment of backdoors, modification of security policies, or complete system compromise through unauthorized software installation.
The operational impact of this vulnerability extends beyond simple authentication bypass, as it fundamentally undermines the security posture of organizations relying on these appliances for network protection. Remote attackers can leverage this flaw to silently install malicious software, modify security configurations, or establish persistent access points within the network infrastructure. The attack vector requires no authentication credentials, making it particularly dangerous as it can be exploited from anywhere on the internet. This vulnerability aligns with ATT&CK technique T1078 which covers valid accounts and privilege escalation through legitimate system access. Organizations using affected versions face significant risk of supply chain attacks where malicious updates can be delivered to multiple systems simultaneously.
Mitigation strategies should prioritize immediate deployment of the patched releases provided by Cisco, specifically versions 8.0.2-069, 8.0.2-074, 8.5.7-042, 9.1.0-032, 8.5.2-027, and 9.6.1-019. Network administrators should also implement additional monitoring of update traffic and certificate validation processes to detect potential exploitation attempts. The vulnerability demonstrates the critical importance of secure update mechanisms in security appliances, where the update process itself must be protected against tampering and impersonation attacks. Organizations should consider implementing network segmentation and access controls to limit the potential impact of such attacks, while also maintaining comprehensive logging of all update activities for forensic analysis purposes.