Source: cve@mitre.org
fsdump command in IRIX allows local users to obtain root access by modifying sensitive files.
Local privilege escalation is possible on vulnerable IRIX systems due to a flaw in the fsdump command. An attacker can leverage this vulnerability to gain root access and potentially compromise the entire system, leading to a complete loss of confidentiality, integrity, and availability.
Step 1: Identify Vulnerable System: The attacker identifies a target IRIX system.
Step 2: Locate fsdump: The attacker confirms the presence and version of the fsdump command.
Step 3: File Manipulation: The attacker identifies a sensitive file that fsdump interacts with, such as a file containing user credentials or system configuration.
Step 4: Exploit Trigger: The attacker crafts a malicious input or manipulates file attributes (e.g., permissions, ownership) that fsdump uses during its operation. This could involve creating a symlink, exploiting a format string vulnerability, or triggering a race condition.
Step 5: Privilege Escalation: The attacker executes fsdump with the crafted input or manipulated file.
Step 6: Root Access: The fsdump command, due to the vulnerability, modifies the targeted file in a way that allows the attacker to gain root privileges (e.g., by adding a user with root privileges or modifying the root password).
The vulnerability lies within the fsdump command's handling of file system metadata. Specifically, the command likely fails to properly validate user-controlled input when interacting with sensitive files. This could manifest as a format string vulnerability, a symlink attack, or a TOCTOU (Time-of-Check to Time-of-Use) race condition. The attacker exploits this flaw by manipulating file attributes or contents, such as the ownership or permissions of critical system files (e.g., /etc/shadow, /etc/passwd), leading to unauthorized modification and ultimately, root access. The root cause is a lack of proper input validation and secure file handling within the fsdump command's logic.
Due to the age of this vulnerability, it's unlikely to be directly associated with specific modern APT groups. However, any threat actor targeting legacy systems would likely be interested in this. This vulnerability is not listed in the CISA KEV catalog, but its potential impact on legacy systems warrants attention.
Monitor system logs for unusual activity related to the fsdump command, including unexpected arguments or file access patterns.
Analyze file system changes, particularly modifications to sensitive files like /etc/passwd, /etc/shadow, /etc/group, and system configuration files.
Implement file integrity monitoring (FIM) to detect unauthorized changes to critical system files.
Monitor for the creation of new user accounts with root privileges.
Network monitoring for unusual SSH or other remote access attempts, especially after a potential exploitation attempt.
Apply security patches provided by the vendor (SGI) if available. However, given the age of the vulnerability, patches may not exist.
If patching is not possible, remove or disable the fsdump command if it is not essential for system operation. This is the most effective mitigation.
Restrict access to the fsdump command to only authorized users.
Implement strong file system permissions to prevent unauthorized modification of sensitive files.
Regularly audit system logs and file integrity to detect any suspicious activity.
Consider isolating vulnerable systems from the network or segmenting the network to limit the impact of a potential compromise.