Source: cve@mitre.org
Novell NetMail 3.5.2a, 3.5.2b, and 3.5.2c, when running on Linux, sets the owner and group ID to 500 for certain files, which could allow users or groups with that ID to execute arbitrary code or cause a denial of service by modifying those files.
Novell NetMail versions 3.5.2a, 3.5.2b, and 3.5.2c on Linux are vulnerable to a privilege escalation attack. The software incorrectly sets the owner and group ID of certain files to a common value (500), allowing any user or group with that ID to execute arbitrary code or cause a denial of service by modifying those files.
Step 1: Identify Target Files: The attacker identifies files within the NetMail installation that are owned by user/group ID 500. These files are likely configuration files, scripts, or potentially executable binaries used by the NetMail service.
Step 2: Payload Preparation: The attacker crafts a malicious payload. This could be a malicious script, a modified configuration file, or a compiled binary designed to execute with the privileges of the NetMail service (effectively the privileges of the user/group ID 500).
Step 3: Payload Delivery: The attacker uploads or otherwise places the malicious payload into a location accessible to the vulnerable files. This could involve exploiting other vulnerabilities to gain initial access, or simply placing the payload in a publicly writable directory if such a directory exists and is used by the vulnerable files.
Step 4: Payload Modification: The attacker modifies the target file(s) to include or reference the malicious payload. This could involve overwriting the file contents, appending to the file, or modifying configuration settings to point to the malicious payload.
Step 5: Trigger Execution: The attacker triggers the execution of the modified file(s). This could be achieved by restarting the NetMail service, accessing a specific feature that utilizes the file, or by other means depending on the nature of the vulnerable files.
Step 6: Privilege Escalation: The malicious payload executes with the privileges of the user/group ID 500, allowing the attacker to gain control of the NetMail service or potentially the underlying system.
The vulnerability stems from a flawed implementation of file ownership and permission management within Novell NetMail. Specifically, the software fails to properly restrict access to critical files by assigning them a predictable owner and group ID (500). This creates a privilege escalation opportunity. The root cause is a lack of secure coding practices, where the developers did not anticipate or mitigate the potential for unauthorized modification of these files by users or groups sharing the same ID. The predictable ownership allows attackers to craft malicious payloads and inject them into files that are subsequently executed with elevated privileges. This is not a buffer overflow or race condition vulnerability, but rather a simple permission misconfiguration issue.
Due to the age of the vulnerability and the specific product, it is unlikely to be targeted by sophisticated APTs. However, any attacker with basic skills could exploit this vulnerability. Not listed on CISA KEV.
Monitor file system activity for modifications to files owned by user/group ID 500, especially those related to NetMail.
Analyze NetMail service logs for unusual activity or errors that could indicate exploitation attempts.
Implement file integrity monitoring (FIM) to detect unauthorized changes to critical NetMail files.
Network traffic analysis may reveal suspicious communication patterns if the attacker attempts to exfiltrate data or establish a command-and-control channel.
Upgrade to a patched version of Novell NetMail (if available). Since the product is old, this may not be possible.
If upgrading is not possible, review and manually correct the file ownership and permissions of all NetMail files to ensure that they are owned by the correct user and group IDs and that permissions are set to the least privilege necessary.
Implement a robust file integrity monitoring (FIM) solution to detect any unauthorized changes to critical files.
Regularly audit user and group permissions to identify and correct any misconfigurations.
Isolate the NetMail server from other network resources to limit the impact of a successful exploit.