Source: cve@mitre.org
swinstall and swmodify commands in SD-UX package in HP-UX systems allow local users to create or overwrite arbitrary files to gain root access.
HP-UX systems are vulnerable to a critical local privilege escalation via flaws in the swinstall and swmodify commands. This vulnerability allows attackers to overwrite arbitrary files, including critical system files, enabling them to gain root access and potentially compromise the entire system.
Step 1: Identify Target Files: The attacker identifies critical system files that, when overwritten, could grant root access. This might include files like /etc/passwd, /etc/shadow, or files related to system startup scripts.
Step 2: Craft Malicious Input: The attacker crafts a malicious input, potentially including a symbolic link pointing to a target file, or a specially crafted file containing malicious code.
Step 3: Invoke swinstall/swmodify: The attacker executes the swinstall or swmodify command, providing the malicious input as an argument, typically specifying the location of the target file.
Step 4: File Overwrite: Due to the vulnerability, the swinstall or swmodify command, operating with elevated privileges, overwrites the target file with the attacker's malicious input.
Step 5: Privilege Escalation: The attacker leverages the overwritten file to gain root access. For example, overwriting /etc/passwd allows the attacker to create a new user with root privileges. Overwriting a startup script could allow the attacker to execute arbitrary code at system boot.
The vulnerability stems from insecure handling of file permissions and pathnames within the swinstall and swmodify utilities, part of the SD-UX package. Specifically, these commands fail to properly validate user-supplied input when specifying file locations for installation or modification. This lack of input validation allows a local user to craft malicious input, such as a symbolic link or a specially crafted file, to overwrite critical system files. The root cause is a combination of inadequate input sanitization and insufficient permission checks during file operations. This can lead to the creation of files with elevated privileges, or the modification of existing files, ultimately granting the attacker root access. The commands likely operate with elevated privileges, and the lack of proper checks allows the attacker to leverage this to their advantage. The vulnerability is exacerbated by the fact that the SD-UX package is a core component of HP-UX systems, making it a high-value target.
While no specific APTs are directly linked to this CVE, it is a type of vulnerability that is commonly exploited by various threat actors. This is a classic local privilege escalation vulnerability. This vulnerability is not listed in the CISA KEV. However, this does not mean it is not a target, as older vulnerabilities are often exploited by less sophisticated actors or as part of a larger attack chain.
Monitor system logs for suspicious activity related to swinstall and swmodify commands, especially those involving file modifications in sensitive directories (e.g., /etc, /usr/sbin).
Analyze file modification timestamps and checksums to identify unexpected changes to critical system files.
Implement file integrity monitoring (FIM) tools to detect unauthorized modifications to system files.
Review user accounts and their privileges, looking for newly created root accounts or changes to existing root accounts.
Network traffic analysis: While this is a local vulnerability, any subsequent network activity from the compromised host should be investigated.
Apply the latest security patches provided by HP for the affected HP-UX versions. This is the primary and most effective remediation step.
Implement strong access controls and restrict the use of swinstall and swmodify commands to authorized users only.
Regularly audit system configurations and user accounts to identify and remediate any potential vulnerabilities.
Implement a file integrity monitoring (FIM) solution to detect unauthorized changes to critical system files.
Consider upgrading to a supported version of HP-UX if possible.
Review and harden system permissions to prevent unauthorized file modifications.