CVE-2010-3135 in Packet Tracer
Summary
by MITRE
Untrusted search path vulnerability in Cisco Packet Tracer 5.2 allows local users, and possibly remote attackers, to execute arbitrary code and conduct DLL hijacking attacks via a Trojan horse wintab32.dll that is located in the same folder as a .pkt or .pkz file.
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Analysis
by VulDB Data Team • 01/07/2018
The vulnerability identified as CVE-2010-3135 represents a critical untrusted search path issue within Cisco Packet Tracer 5.2 that exposes the application to arbitrary code execution and DLL hijacking attacks. This flaw arises from the application's improper handling of dynamic link library loading mechanisms, specifically when processing packet capture files with extensions .pkt or .pkz. The vulnerability demonstrates a classic security weakness where the software fails to properly validate or restrict the search path used to locate required dynamic libraries, creating an exploitable condition that can be leveraged by malicious actors.
The technical implementation of this vulnerability stems from Cisco Packet Tracer's default behavior of searching for required DLL files in the same directory as the target file being processed. When a user opens a malicious .pkt or .pkz file, the application attempts to load the wintab32.dll library from the current working directory without proper validation or path sanitization. This search path weakness creates an opportunity for attackers to place a malicious Trojan horse wintab32.dll file in the same directory as the legitimate packet capture file, thereby enabling successful DLL hijacking attacks that can execute arbitrary code with the privileges of the affected user.
From an operational perspective, this vulnerability presents a significant risk to organizations using Cisco Packet Tracer for network simulation and educational purposes. The attack vector can be either local or remote, depending on how the malicious file is delivered to the target system, making it particularly dangerous in environments where users may open untrusted packet capture files from unknown sources. The vulnerability directly maps to CWE-427 Uncontrolled Search Path Element, which specifically addresses the issue of applications using untrusted search paths that can be manipulated to load malicious code. This weakness can be exploited through various attack techniques including social engineering campaigns that deliver malicious packet files, or through compromised network environments where attackers can place malicious DLL files in accessible directories.
The impact of successful exploitation extends beyond simple code execution to potentially full system compromise, as the malicious DLL can leverage the privileges of the running application to perform unauthorized actions. This vulnerability aligns with several ATT&CK techniques including T1059 Command and Scripting Interpreter and T1574 DLL Side-Loading, demonstrating how attackers can manipulate legitimate system processes to execute malicious payloads. Organizations relying on Cisco Packet Tracer for network education or simulation activities face significant risk exposure, particularly in environments where users may encounter untrusted packet files from external sources. The vulnerability also highlights the importance of proper privilege separation and secure coding practices in application development, specifically in how applications handle dynamic library loading and path resolution.
Mitigation strategies should focus on immediate patching of the vulnerable Cisco Packet Tracer version, implementing strict file access controls to prevent unauthorized DLL placement in user directories, and establishing proper application whitelisting policies. System administrators should also consider implementing monitoring for suspicious DLL loading activities and conducting regular security assessments of network simulation environments. The vulnerability underscores the necessity of following secure coding practices such as using absolute paths for library loading, implementing proper DLL search path restrictions, and employing code signing validation to prevent unauthorized code execution. Organizations should also consider alternative network simulation tools that have been properly vetted for secure library loading mechanisms and have demonstrated robust security practices in their development lifecycle.