CVE-2016-8231 in Service Bridge
Summary
by MITRE
In Lenovo Service Bridge before version 4, a bug found in the signature verification logic of the code signing certificate could be exploited by an attacker to insert a forged code signing certificate.
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Analysis
by VulDB Data Team • 10/13/2019
The vulnerability identified as CVE-2016-8231 affects Lenovo Service Bridge software versions prior to 4.0, representing a critical flaw in the code signing certificate verification mechanism. This issue stems from inadequate signature validation logic that fails to properly authenticate the legitimacy of code signing certificates. The vulnerability creates a pathway for malicious actors to bypass security controls by inserting forged certificates that appear to be legitimate code signing certificates issued by Lenovo. Such a flaw fundamentally undermines the integrity of the software supply chain and compromises the trust model that code signing is designed to establish.
The technical implementation of this vulnerability resides in the signature verification algorithm within the Lenovo Service Bridge component. The flaw manifests when the system processes code signing certificates and fails to perform comprehensive validation checks that should confirm certificate authenticity, issuer legitimacy, and cryptographic integrity. Attackers can exploit this weakness by crafting malicious certificates that satisfy the superficial validation requirements while bypassing deeper cryptographic verification steps. This vulnerability aligns with CWE-311, which describes the exposure of sensitive data due to insufficient or improper cryptographic protection mechanisms, and represents a significant deviation from proper certificate validation practices.
The operational impact of CVE-2016-8231 extends beyond simple code execution privileges, as it enables attackers to potentially compromise the entire system integrity through malicious code injection. When exploited, this vulnerability allows adversaries to install unauthorized software, modify existing applications, or execute arbitrary code with elevated privileges. The attack vector typically involves installing a forged certificate that appears legitimate to the system's verification process, thereby enabling the execution of malicious payloads that would otherwise be blocked by standard security controls. This weakness particularly affects enterprise environments where Lenovo Service Bridge is deployed, as it provides a persistent backdoor for attackers to maintain long-term access to target systems.
Organizations should implement immediate mitigation strategies including updating to Lenovo Service Bridge version 4.0 or later, which contains the corrected signature verification logic. System administrators should also conduct comprehensive vulnerability assessments to identify any potentially compromised systems that may have been exposed to this vulnerability prior to patching. Additionally, security teams should monitor for suspicious certificate installations and implement enhanced certificate monitoring procedures to detect unauthorized certificate modifications. The mitigation approach should align with ATT&CK technique T1553.002, which focuses on code signing bypass methods, ensuring that defensive measures address both the immediate vulnerability and broader attack patterns that leverage similar weaknesses in certificate validation processes.