CVE-2015-8110 in System Update
Summary
by MITRE
Lenovo System Update (formerly ThinkVantage System Update) before 5.07.0019 allows local users to gain privileges by navigating to (1) "Click here to learn more" or (2) "View privacy policy" within the Tvsukernel.exe GUI application in the context of a temporary administrator account, aka a "local privilege escalation vulnerability."
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Analysis
by VulDB Data Team • 12/21/2020
The vulnerability identified as CVE-2015-8110 represents a critical local privilege escalation flaw within Lenovo System Update, formerly known as ThinkVantage System Update, affecting versions prior to 5.07.0019. This vulnerability specifically targets the Tvsukernel.exe GUI application component that operates within temporary administrator account contexts, creating a significant security risk for systems running affected software versions. The flaw exploits the application's handling of user interactions with specific hyperlinks within its graphical interface, allowing unauthorized local users to elevate their privileges from standard user level to administrator access. This represents a fundamental failure in privilege management and access control mechanisms within the software's design.
The technical implementation of this vulnerability stems from improper privilege validation and execution flow within the Tvsukernel.exe application. When users interact with either the "Click here to learn more" or "View privacy policy" hyperlinks present in the application's graphical user interface, the software fails to properly validate the current user context before executing privileged operations. This creates a path where a local user can leverage these seemingly benign navigation actions to trigger elevated privilege execution contexts. The vulnerability operates under the principle of insufficient privilege checking, where the application assumes that certain user interactions should not require additional authorization checks. This flaw directly relates to CWE-284, which addresses improper access control mechanisms, and demonstrates how GUI-based navigation elements can serve as attack vectors for privilege escalation.
The operational impact of this vulnerability extends beyond simple privilege elevation, as it provides attackers with a persistent means of gaining administrative control over affected systems. Once successfully exploited, the vulnerability allows attackers to execute arbitrary code with full administrative privileges, potentially enabling complete system compromise, data exfiltration, and persistent backdoor installation. The vulnerability is particularly concerning because it can be exploited by local users who may not have initial administrative access, making it a significant threat vector for both malicious actors and insider threats. The attack requires minimal technical expertise since it leverages the application's own interface elements to achieve privilege escalation, making it particularly dangerous in enterprise environments where multiple users may have access to affected systems. This vulnerability aligns with ATT&CK technique T1068, which covers local privilege escalation through the exploitation of software vulnerabilities.
Mitigation strategies for CVE-2015-8110 should prioritize immediate software updates to version 5.07.0019 or later, which contains the necessary patches to address the privilege escalation flaw. Organizations should implement comprehensive patch management procedures to ensure all affected Lenovo System Update installations are updated promptly. Additionally, system administrators should consider implementing additional security controls such as application whitelisting policies that restrict execution of potentially vulnerable applications. Network segmentation and user access controls should be reviewed to minimize the potential impact of successful exploitation. The vulnerability demonstrates the importance of proper privilege separation and access control validation in GUI applications, particularly those that may operate in elevated contexts. Organizations should also consider conducting security assessments of similar update mechanisms across their enterprise to identify potential similar vulnerabilities. The remediation process should include verification that the updated software properly validates user contexts before executing privileged operations, ensuring that the fix addresses the root cause rather than merely masking symptoms of the vulnerability.