CVE-2016-7838 in WinSparkle
Summary
by MITRE
Untrusted search path vulnerability in WinSparkle versions prior to 0.5.3 allows remote attackers to execute arbitrary code via a specially crafted executable file in an unspecified directory.
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Analysis
by VulDB Data Team • 12/08/2022
The vulnerability identified as CVE-2016-7838 represents a critical untrusted search path issue affecting WinSparkle versions prior to 053. This flaw resides in the software update mechanism of WinSparkle, a popular library used by Windows applications to provide automatic updates. The vulnerability stems from the application's failure to properly validate file paths during the update process, creating an exploitable condition where malicious actors can manipulate the update workflow. The affected versions of WinSparkle do not implement proper path sanitization when processing update files, allowing attackers to place malicious executables in directories that are automatically searched during the update procedure. This vulnerability falls under the CWE-427 weakness category, which specifically addresses uncontrolled search path, and aligns with ATT&CK technique T1059.001 for execution through command and scripting interpreter.
The technical exploitation of this vulnerability requires an attacker to place a specially crafted malicious executable in a directory that WinSparkle will traverse during its update process. The flaw occurs because WinSparkle does not enforce strict path validation when resolving update files, enabling attackers to manipulate the search order and potentially execute arbitrary code with the privileges of the user running the vulnerable application. This issue is particularly dangerous because it can be triggered remotely through the update mechanism of applications using WinSparkle, without requiring local system access or user interaction beyond the normal update process. The vulnerability essentially allows for privilege escalation and code execution, as the malicious file gets executed in the context of the legitimate application process. This creates a significant risk for enterprise environments where applications using WinSparkle are deployed across multiple systems.
The operational impact of CVE-2016-7838 extends beyond individual system compromise to potentially affect entire application ecosystems that rely on WinSparkle for updates. Applications using vulnerable versions of WinSparkle could become vectors for broader attacks, especially in environments where users have elevated privileges or where the applications run with administrative rights. The vulnerability's remote exploitability means that attackers can initiate the attack from anywhere on the network, making it particularly concerning for organizations with limited network segmentation. Security teams must consider the potential for lateral movement through compromised applications, as the malicious update process could be used to establish persistent access or deploy additional malware. The vulnerability also impacts the trust model of the update system, potentially undermining user confidence in application security and update mechanisms.
Mitigation strategies for CVE-2016-7838 focus primarily on updating to WinSparkle version 053 or later, which contains the necessary patches to address the untrusted search path vulnerability. Organizations should conduct comprehensive inventory assessments to identify all applications using vulnerable versions of WinSparkle and prioritize their remediation. System administrators should implement network monitoring to detect unusual update activity or file creation patterns that might indicate exploitation attempts. Additional protective measures include restricting write permissions to directories used by WinSparkle update processes, implementing application whitelisting policies, and conducting regular security assessments of update mechanisms. The fix implemented in WinSparkle 053 involves strengthening path validation and ensuring that update files are resolved through controlled paths rather than allowing arbitrary directory traversal. Organizations should also consider deploying endpoint protection solutions that can detect and prevent the execution of suspicious files in update directories, as this vulnerability can be exploited through various attack vectors including phishing campaigns or compromised update servers.