CVE-2010-5220 in MEO Encryption Software
Summary
by MITRE
Untrusted search path vulnerability in MEO Encryption Software 2.02 allows local users to gain privileges via a Trojan horse dwmapi.dll file in the current working directory, as demonstrated by a directory that contains a .meo or .cry file. NOTE: some of these details are obtained from third party information.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 01/31/2018
The vulnerability identified as CVE-2010-5220 represents a critical untrusted search path weakness in MEO Encryption Software version 2.02 that enables local privilege escalation through malicious Trojan horse file placement. This flaw operates on the fundamental principle of insecure library loading where the software fails to properly validate the source and integrity of dynamically loaded components. The vulnerability specifically manifests when the encryption software processes files with .meo or .cry extensions, creating a scenario where an attacker can place a malicious dwmapi.dll file in the same directory as these encrypted files, thereby exploiting the software's trust in the current working directory for library resolution.
The technical implementation of this vulnerability stems from the software's improper handling of dynamic link library loading mechanisms. When MEO Encryption Software encounters a .meo or .cry file, it attempts to load system libraries from the current working directory without sufficient validation of the library's authenticity or origin. This behavior aligns with CWE-427 Uncontrolled Search Path Element, which describes situations where applications search for libraries in directories specified by the user or environment without proper sanitization. The dwmapi.dll file serves as the malicious payload that, when loaded, can execute arbitrary code with the privileges of the user running the encryption software, effectively creating a privilege escalation vector.
Operationally, this vulnerability presents significant risk to systems running the affected software since it requires only local user access to exploit. An attacker need only place a crafted dwmapi.dll file in the directory containing the target .meo or .cry files, then trigger the encryption software to process these files. The impact extends beyond simple privilege escalation to potential full system compromise, as the malicious code can leverage the elevated privileges to modify system files, install additional malware, or establish persistent access. This vulnerability also aligns with ATT&CK technique T1068 Privilege Escalation through the use of a local exploit to gain higher privileges, and specifically maps to T1547.001 Registry Run Keys / Startup Folder which could be employed to maintain persistence after the initial exploitation.
Mitigation strategies for CVE-2010-5220 should focus on both immediate remediation and long-term architectural improvements. The most effective immediate solution involves updating to a patched version of MEO Encryption Software that properly implements secure library loading practices. Organizations should also implement directory access controls and file system monitoring to detect unauthorized DLL placement in directories containing encrypted files. Additionally, system administrators should consider implementing application whitelisting policies that restrict which libraries can be loaded by the encryption software, and employ security tools that monitor for suspicious dynamic library loading activities. The vulnerability demonstrates the importance of following secure coding practices such as those outlined in the CERT Secure Coding Standards, particularly guidelines regarding proper library path resolution and avoiding insecure search path behaviors that could be exploited by attackers to gain unauthorized access to system resources.