CVE-2006-3784 in pcAnywhere
Summary
by MITRE
Symantec pcAnywhere 12.5 uses weak default permissions for the "Symantec\pcAnywhere\Hosts" folder, which allows local users to gain privileges by inserting a superuser .cif (aka caller or CallerID) file into the folder, and then using a pcAnywhere client to login as a local administrator.
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Analysis
by VulDB Data Team • 04/07/2017
The vulnerability described in CVE-2006-3784 represents a critical privilege escalation flaw within Symantec pcAnywhere version 12.5, a remote desktop and system management tool widely used in enterprise environments. This weakness stems from inadequate default security configurations that fail to properly restrict access permissions for critical system components. The vulnerability specifically targets the "Symantec\pcAnywhere\Hosts" directory structure, which serves as a repository for authentication and authorization data necessary for remote system access. The flaw enables local attackers to manipulate the system's trust relationships by leveraging the system's insufficient permission controls, creating a pathway for unauthorized privilege elevation. This type of vulnerability directly impacts the principle of least privilege and demonstrates poor security by design practices in the software's installation and configuration.
The technical implementation of this vulnerability exploits a fundamental flaw in access control mechanisms within the pcAnywhere application. The weak default permissions for the Hosts folder allow any local user to write or modify files within this critical directory structure. When an attacker successfully places a specially crafted .cif file containing superuser credentials or elevated privileges, the system's authentication process interprets this file as legitimate and grants administrative access to the attacker. This process bypasses normal authentication procedures and demonstrates a classic path traversal and privilege escalation vulnerability. The .cif file format serves as a CallerID mechanism that the pcAnywhere client uses to verify and authenticate incoming connection requests, making this attack vector particularly dangerous as it allows an attacker to effectively impersonate system administrators. The vulnerability operates at the operating system level, leveraging local file system permissions rather than network-based attacks, which makes it particularly difficult to detect through traditional network monitoring approaches.
The operational impact of this vulnerability extends far beyond simple privilege escalation, creating significant security risks for organizations relying on pcAnywhere for remote system management. Local attackers with minimal privileges can effectively gain complete administrative control over systems running vulnerable versions of pcAnywhere, potentially leading to full system compromise, data exfiltration, and lateral movement within network environments. The attack requires only local system access and file system write permissions, making it accessible to users who may not have legitimate administrative privileges. This vulnerability essentially undermines the security model of the entire pcAnywhere platform, as it allows attackers to bypass the software's intended access controls and authentication mechanisms. Organizations using pcAnywhere for remote administration may unknowingly provide attackers with a backdoor that enables persistent access and privilege escalation without requiring additional attack vectors or sophisticated exploitation techniques.
The mitigation strategies for this vulnerability involve immediate remediation through proper permission configuration and software updates. System administrators should immediately review and correct the default permissions for the "Symantec\pcAnywhere\Hosts" folder, ensuring that only authorized system administrators or specific service accounts have write access to this directory. The recommended approach includes implementing restrictive access control lists that prevent local users from modifying critical system files, particularly those used for authentication and authorization. Additionally, organizations should consider implementing file integrity monitoring solutions that can detect unauthorized modifications to critical system directories. The vulnerability aligns with CWE-276, which addresses improper permissions for critical resources, and represents a clear violation of the principle of least privilege. From an ATT&CK perspective, this vulnerability maps to privilege escalation techniques and can be categorized under T1068, which involves local privilege escalation through service exploitation or file system manipulation. Regular security audits and proper access control reviews should be implemented to prevent similar issues in other software components and ensure that default installations do not create security vulnerabilities that could be exploited by local users.