CVE-2006-3786 in pcAnywhere
Summary
by MITRE
Symantec pcAnywhere 12.5 uses weak integrity protection for .cif (aka caller or CallerID) files, which allows local users to generate a custom .cif file and modify the superuser flag.
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Analysis
by VulDB Data Team • 04/07/2017
Symantec pcAnywhere 12.5 suffers from a critical integrity protection weakness in its handling of .cif files, which are essential for caller identification and authentication within the remote access system. These files contain crucial authentication data including user credentials and privilege levels that determine system access rights. The vulnerability stems from insufficient cryptographic protection mechanisms that fail to properly validate file integrity, allowing malicious actors with local system access to manipulate these files without detection. This weakness directly impacts the security model of pcAnywhere by undermining the authentication process that relies on these caller identification files to establish trust boundaries between remote users and the target system.
The technical flaw manifests in the absence of robust digital signatures or cryptographic checksums within the .cif file format. Attackers can exploit this gap by creating custom .cif files that contain modified superuser flags, effectively granting themselves elevated privileges within the pcAnywhere environment. The vulnerability operates at the file system level, requiring only local access to the target machine, which significantly reduces the attack surface compared to network-based exploits. This weakness enables privilege escalation attacks where a local user can transform their regular account into a superuser account simply by modifying the appropriate fields within the .cif file structure. The system fails to verify the authenticity of these files during the authentication process, creating a persistent backdoor mechanism that can be exploited repeatedly.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally compromises the integrity of the entire pcAnywhere authentication framework. Once an attacker gains superuser privileges through this method, they can bypass all other security controls within the pcAnywhere system, including access restrictions, session management, and encryption protocols. This vulnerability creates a persistent threat vector that can be exploited by malware or insider threats, as the modified .cif files remain undetected by standard security monitoring systems. The weakness also affects the system's ability to maintain audit trails and accountability, since the authentication process cannot reliably verify user identities or privilege levels. Organizations relying on pcAnywhere for remote system administration face significant risk of unauthorized access and potential data breaches, as the vulnerability allows attackers to assume full administrative control without detection.
Mitigation strategies should focus on implementing proper cryptographic integrity checks for all .cif files and enhancing the authentication verification process within pcAnywhere. System administrators should disable unnecessary local access to pcAnywhere configuration files and implement strict file permission controls to prevent unauthorized modification. The vulnerability aligns with CWE-310, which addresses cryptographic weakness in authentication mechanisms, and relates to ATT&CK technique T1548.001 for privilege escalation through legitimate credentials. Organizations should consider upgrading to newer versions of pcAnywhere that implement proper cryptographic protection for configuration files or migrating to more secure remote access solutions that provide robust integrity verification. Regular security audits should include verification of file integrity for all authentication-related configuration files, and monitoring systems should be enhanced to detect anomalous modifications to critical system files. Additionally, implementing principle of least privilege access controls and disabling unnecessary local accounts can significantly reduce the risk of exploitation.