CVE-2010-3129 in uTorrent
Summary
by MITRE
Untrusted search path vulnerability in uTorrent 2.0.3 and earlier allows local users, and possibly remote attackers, to execute arbitrary code and conduct DLL hijacking attacks via a Trojan horse plugin_dll.dll, userenv.dll, shfolder.dll, dnsapi.dll, dwmapi.dll, iphlpapi.dll, dhcpcsvc.dll, dhcpcsvc6.dll, or rpcrtremote.dll that is located in the same folder as a .torrent or .btsearch file.
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Analysis
by VulDB Data Team • 03/03/2017
The vulnerability identified as CVE-2010-3129 represents a critical untrusted search path issue affecting uTorrent versions 2.0.3 and earlier, which creates a significant attack surface for both local and remote threat actors. This flaw resides in the application's dynamic link library loading mechanism, where the software fails to properly validate the source and integrity of dynamically loaded libraries. The vulnerability specifically manifests when uTorrent processes torrent files or search result files, as the application searches for required DLL components in the same directory as these files, rather than in system-protected locations. This behavior creates an exploitable condition where malicious actors can place specially crafted DLL files in the same directory as legitimate torrent files, leading to arbitrary code execution when the application loads these components. The affected DLLs include common system libraries such as plugin_dll.dll, userenv.dll, shfolder.dll, dnsapi.dll, dwmapi.dll, iphlpapi.dll, dhcpcsvc.dll, dhcpcsvc6.dll, and rpcrtremote.dll, which are commonly present in Windows environments and can be leveraged to execute malicious payloads with elevated privileges. This vulnerability aligns with CWE-427 Uncontrolled Search Path Element, which specifically addresses the dangerous practice of allowing applications to load libraries from untrusted directories, and represents a classic DLL hijacking attack vector that has been widely documented in cybersecurity literature. The attack requires minimal privileges for local exploitation and can potentially be extended to remote scenarios when attackers can influence the placement of malicious files in directories where users might download torrent files.
The technical exploitation of this vulnerability relies on the fundamental flaw in uTorrent's library resolution process, which does not implement proper security checks during dynamic library loading. When uTorrent encounters a torrent file or search result file, it automatically searches for required dependencies in the local directory, a behavior that violates the principle of least privilege and secure coding practices. The attack vector is particularly dangerous because it can be initiated through various means including social engineering, compromised websites, or malicious torrent file distribution. Attackers can place malicious DLL files with names matching those required by uTorrent, and when users open the torrent files, the application will load these malicious components instead of legitimate system libraries. This creates a persistent threat that can be maintained across multiple sessions, as the malicious DLLs remain in the directory and will be loaded whenever the application processes files from that location. The vulnerability essentially allows attackers to execute arbitrary code with the privileges of the user running uTorrent, potentially leading to complete system compromise, data exfiltration, or the installation of additional malware. The exploitation process is streamlined because the attacker only needs to place malicious files in the same directory as the target files, without requiring direct access to system-level resources or complex attack chains.
The operational impact of CVE-2010-3129 extends far beyond simple code execution, as it can facilitate comprehensive system compromise and persistent threats within infected environments. Local attackers can leverage this vulnerability to escalate privileges and gain control over user sessions, while remote attackers can potentially deliver malicious payloads through compromised torrent distribution networks or malicious websites. The vulnerability affects the core functionality of uTorrent, making it particularly dangerous as it can be exploited without user awareness, especially when users download torrents from untrusted sources. The attack can result in the installation of backdoors, keyloggers, or other persistent malware that can remain undetected while providing attackers with long-term access to compromised systems. Additionally, the vulnerability can be chained with other exploits or used as a foothold for more sophisticated attacks within enterprise networks, particularly in environments where torrent clients are commonly used for file sharing. The impact is amplified by the widespread use of uTorrent, which means that a single vulnerable installation can serve as a vector for large-scale attacks. The vulnerability also demonstrates the importance of secure coding practices in client-side applications, as the issue stems from poor library loading mechanisms rather than complex cryptographic flaws. This makes the vulnerability particularly concerning because it affects software that is widely used and often runs with elevated privileges during file operations, creating multiple potential attack vectors for threat actors.
Mitigation strategies for CVE-2010-3129 must address both the immediate vulnerability and broader security practices within affected environments. The primary recommendation is to upgrade to uTorrent versions that have addressed this vulnerability, as the developers have implemented proper library loading mechanisms that prevent loading DLLs from untrusted directories. Organizations should also implement strict file access controls and monitoring of directories where torrent files are processed, particularly those containing user-generated content or files from untrusted sources. Network segmentation and application whitelisting can help prevent the execution of unauthorized DLL files, while regular security audits should include checks for vulnerable software installations. Users should be educated about the risks of downloading torrent files from untrusted sources and the importance of verifying file integrity before opening them. System administrators should consider implementing security solutions that monitor for suspicious DLL loading activities and can detect when applications are attempting to load libraries from unexpected locations. Additionally, the vulnerability highlights the need for secure coding practices and the importance of following the principle of least privilege when developing client applications. The mitigation approach should also include regular patch management processes to ensure that all vulnerable applications are kept up to date with security fixes, as this vulnerability represents a known weakness that has been addressed in subsequent software versions. Organizations should also consider implementing endpoint protection solutions that can detect and block DLL hijacking attempts, providing an additional layer of defense against this type of attack.