CVE-2017-10824 in CA TypeA
Summary
by MITRE
Untrusted search path vulnerability in TDB CA TypeA use software Version 5.2 and earlier, distributed until 10 August 2017 allows an attacker to gain privileges via a Trojan horse DLL in an unspecified directory.
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Analysis
by VulDB Data Team • 11/08/2019
The vulnerability identified as CVE-2017-10824 represents a critical untrusted search path issue within the TDB CA TypeA use software version 5.2 and earlier, which was distributed until August 10, 2017. This flaw resides in the software's dynamic link library loading mechanism, where the application fails to properly validate the source and integrity of dynamically loaded modules. The vulnerability manifests when the software attempts to load DLL files from directories that are not properly secured or validated, creating an attack surface where malicious actors can place Trojan horse DLLs in strategic locations within the file system.
The technical implementation of this vulnerability stems from the software's improper handling of the Windows dynamic link library search order, which follows a predictable sequence of directory traversal. When the TDB CA TypeA use software executes, it searches for required DLL components in a specific order including the current working directory, system directories, and user-specified paths. Attackers can exploit this behavior by placing a malicious DLL with the same name as a legitimate library in a directory that gets searched before the legitimate library location, effectively causing the software to load the malicious component instead of the intended secure version. This behavior aligns with CWE-427, which describes uncontrolled search path dependencies, and represents a classic privilege escalation vector.
The operational impact of this vulnerability extends beyond simple code execution, as it enables attackers to achieve elevated privileges within the system where the vulnerable software operates. When an attacker successfully places a malicious DLL in the search path, the software will execute code with the privileges of the user running the application, potentially allowing for system compromise, data exfiltration, or further lateral movement within the network. The vulnerability is particularly concerning because it can be exploited without requiring direct user interaction, making it a stealthy attack vector that could go undetected for extended periods. This type of vulnerability commonly maps to ATT&CK technique T1059.001 for command and scripting interpreter usage and T1068 for exploit for privilege escalation.
Mitigation strategies for CVE-2017-10824 should focus on addressing the root cause of the untrusted search path behavior through multiple defensive layers. Organizations should implement strict directory permissions and access controls to prevent unauthorized DLL placement in critical system paths, while also ensuring that the software is updated to versions that properly validate DLL sources. The recommended approach includes configuring the software to use absolute paths for DLL loading, implementing application whitelisting policies, and conducting regular security audits of the file system to detect unauthorized DLL placements. Additionally, system administrators should consider implementing Windows Defender Application Control or similar technologies to enforce code integrity policies and prevent execution of unauthorized DLLs. The vulnerability underscores the importance of secure coding practices and proper input validation, particularly when dealing with dynamic library loading mechanisms, and demonstrates why adherence to security standards like those outlined in the CWE database and MITRE ATT&CK framework is essential for preventing such exploitations.