A critical buffer overflow vulnerability in Symantec pcAnywhere, identified as CVE-2011-3478, allows unauthenticated attackers to execute arbitrary code with SYSTEM privileges. This flaw, present in the awhost32 component, stems from improper handling of authentication requests on TCP port 5631. The vulnerability was assigned a CVSS score of 9.7, reflecting its severe impact on affected systems1.
Technical Breakdown
The vulnerability arises due to unsafe copying of user-supplied usernames into a fixed-length buffer of 0x108 bytes during authentication. This buffer overflow can lead to remote code execution (RCE) or denial of service (DoS). Exploitation requires no authentication, making it particularly dangerous for exposed systems. The flaw affects pcAnywhere versions 12.5.x through 12.5.3 and IT Management Suite pcAnywhere Solution 7.0 (12.5.x) and 7.1 (12.6.x)2.
Proof-of-concept (PoC) exploits, including a Metasploit module and a Python script, demonstrate the feasibility of RCE via crafted username and password fields. The Python PoC, documented in Exploit-DB #38599, highlights the simplicity of triggering the overflow3. Additional tools like CANVAS and Core Impact have also incorporated exploitation capabilities for this vulnerability.
Mitigation and Remediation
Symantec released a hotfix (TECH182142) to address this issue. Organizations still relying on pcAnywhere should apply this patch immediately. For systems where pcAnywhere is no longer in use, disabling the service entirely is recommended. The 2012 theft of pcAnywhere source code further exacerbated exploitation risks, underscoring the need for prompt action4.
Modern alternatives like AnyViewer, which offer end-to-end encryption and two-factor authentication, provide more secure remote access solutions. Given pcAnywhere’s discontinuation in 2013, migration to supported platforms is strongly advised for long-term security5.
Relevance to Security Professionals
This vulnerability serves as a case study in legacy system risks and the importance of patch management. The availability of multiple exploit vectors, including Metasploit integration, makes it a likely target for opportunistic attacks. Network defenders should prioritize identifying and patching or isolating affected systems, particularly those exposed to the internet.
For offensive security professionals, the vulnerability demonstrates classic buffer overflow exploitation techniques in a real-world application. The public availability of PoCs allows for realistic testing of detection and prevention mechanisms in controlled environments.
Conclusion
CVE-2011-3478 represents a severe vulnerability in a widely deployed remote access solution. While patches exist, the continued use of outdated pcAnywhere versions in some environments poses significant risk. This case highlights the critical need for timely updates and the replacement of end-of-life software with modern, supported alternatives.
References
- “ZDI-12-018: Symantec pcAnywhere Remote Code Execution Vulnerability,” Zero Day Initiative, 2012. [Online]. Available: https://www.zerodayinitiative.com/advisories/ZDI-12-018/
- “Symantec Security Response,” Symantec Corporation, 2012. [Online]. Available: https://www.symantec.com/security_response/securityupdates/detail.jsp?fid=security_advisory&suid=20120124_00
- “Exploit-DB #38599: Symantec pcAnywhere 12.5.3 – Remote Code Execution,” Offensive Security, 2012. [Online]. Available: https://www.exploit-db.com/exploits/38599
- “Tenable Plugin #58119: Symantec pcAnywhere Multiple Vulnerabilities,” Tenable, 2012. [Online]. Available: https://www.tenable.com/plugins/nessus/58119
- “Broadcom Security Center: Symantec pcAnywhere Vulnerability,” Broadcom Inc., 2012. [Online]. Available: https://www.broadcom.com/support/security-center/securityupdates/detail?fid=security_advisory&suid=20120124_00
