CVE-2009-0538 in pcAnywhere
Summary
by MITRE
Format string vulnerability in Symantec pcAnywhere before 12.5 SP1 allows local users to read and modify arbitrary memory locations, and cause a denial of service (application crash) or possibly have unspecified other impact, via format string specifiers in the pathname of a remote control file (aka .CHF file).
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Analysis
by VulDB Data Team • 05/11/2025
The CVE-2009-0538 vulnerability represents a critical format string flaw in Symantec pcAnywhere versions prior to 12.5 SP1 that exposes the application to significant security risks. This vulnerability specifically affects the handling of remote control files with the .CHF extension, which are used to store configuration data for remote desktop sessions. The flaw occurs when the application processes format string specifiers contained within the pathname of these files, creating an opportunity for malicious actors to manipulate memory operations through crafted input data.
This vulnerability falls under the CWE-134 category of format string vulnerability, which is a well-documented weakness in software applications that improperly handle format strings. The technical implementation flaw stems from the application's failure to properly validate and sanitize user-supplied data when processing .CHF file paths. When the pcAnywhere application encounters format specifiers such as %s, %d, or %x within the file path, it does not properly escape or validate these characters, allowing attackers to inject malicious format specifiers that can be interpreted by the underlying printf-family functions. The vulnerability is particularly dangerous because it operates at the local user level, meaning that an attacker with local access to the system can exploit this weakness without requiring network connectivity or elevated privileges.
The operational impact of this vulnerability extends beyond simple denial of service conditions to encompass potential memory corruption and arbitrary code execution scenarios. Local users can leverage this vulnerability to read arbitrary memory locations, which may expose sensitive information such as encryption keys, session tokens, or other confidential data stored in memory. The application crash resulting from memory corruption can lead to persistent denial of service conditions that prevent legitimate users from accessing the remote desktop functionality. Additionally, the unspecified other impacts mentioned in the vulnerability description suggest that attackers might be able to manipulate memory contents in ways that could lead to privilege escalation or further system compromise, making this vulnerability particularly concerning for enterprise environments where pcAnywhere is deployed.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1068 for exploit for privilege escalation. The local privilege escalation aspect becomes particularly relevant when considering that pcAnywhere often runs with elevated privileges to manage remote desktop sessions, making successful exploitation potentially more impactful. The vulnerability also maps to ATT&CK technique T1555.001 for credentials from password storage components, as memory reads could potentially expose authentication credentials or session information. Organizations should consider this vulnerability as part of a broader attack surface assessment, particularly when pcAnywhere is used in environments where local access controls are insufficient or where the application is configured to run with elevated privileges.
The recommended mitigation strategy for CVE-2009-0538 involves immediate deployment of Symantec pcAnywhere 12.5 SP1 or later versions that contain the necessary patches to address the format string vulnerability. System administrators should also implement strict access controls to limit local user access to pcAnywhere installations and ensure that the application is not running with unnecessary elevated privileges. Additional defensive measures include implementing application whitelisting policies that restrict the execution of unauthorized applications, conducting regular vulnerability assessments of legacy software installations, and monitoring for suspicious file creation patterns in directories where .CHF files are processed. Network segmentation and the principle of least privilege should be enforced to minimize the potential impact of successful exploitation attempts, while also ensuring that legacy systems using pcAnywhere are properly isolated from critical network segments.