Source: cve@mitre.org
Vulnerability in hpterm on HP-UX 10.20 allows local users to gain additional privileges.
CVE-1999-0423 describes a critical local privilege escalation vulnerability in the hpterm utility on HP-UX 10.20. Successful exploitation allows attackers to elevate their privileges to root, granting complete control over the compromised system. This vulnerability, though old, highlights the importance of patching and maintaining secure configurations on legacy systems.
Step 1: Identify Target: The attacker identifies a vulnerable HP-UX 10.20 system with hpterm installed.
Step 2: Craft Malicious Input: The attacker crafts a malicious input, likely a long string or a specially formatted environment variable, designed to trigger the vulnerability.
Step 3: Execute hpterm: The attacker executes hpterm with the crafted input. This could involve running hpterm directly or indirectly through another program that calls it.
Step 4: Trigger Memory Corruption: The crafted input causes a buffer overflow or similar memory corruption within the hpterm process.
Step 5: Overwrite Control Flow: The memory corruption overwrites critical data, such as the return address on the stack, redirecting program execution.
Step 6: Execute Payload: The attacker's malicious code (payload), which is either injected directly or pointed to by the overwritten return address, is executed with the privileges of the hpterm process (typically root).
Step 7: Privilege Escalation: The payload grants the attacker root access to the system.
The vulnerability stems from a flaw in the hpterm program's handling of user input or environment variables. The exact mechanism is not explicitly detailed in the CVE description, but it likely involves a buffer overflow or a similar memory corruption issue. The program, running with elevated privileges (potentially setuid root), fails to properly validate the size or content of data it receives, allowing an attacker to overwrite critical memory regions, such as the return address on the stack. This overwrite enables the attacker to redirect program execution to malicious code, ultimately gaining root access. The lack of modern security mitigations, such as stack canaries or ASLR, on older systems like HP-UX 10.20 makes exploitation significantly easier.
While no specific APTs are directly linked to this CVE, it's a type of vulnerability that could be exploited by any threat actor with access to a vulnerable system. It is unlikely to be a primary target for sophisticated APTs, but could be used as part of a broader attack chain. CISA KEV status: Not Listed
Monitor system logs for unusual activity related to hpterm, such as unexpected crashes or errors.
Analyze process execution logs for suspicious command-line arguments or environment variables passed to hpterm.
Use file integrity monitoring to detect modifications to the hpterm executable or related libraries.
Network monitoring for unusual connections originating from the compromised host after hpterm execution.
Apply the latest security patches for HP-UX 10.20. However, support for this version is likely discontinued, making patching difficult or impossible.
If patching is not possible, consider isolating vulnerable systems from the network to limit exposure.
Implement strict access controls to limit user access to hpterm.
Review and harden the system configuration, disabling unnecessary services and features.
Implement a robust intrusion detection and prevention system (IDS/IPS) to monitor for and block malicious activity.
Consider migrating to a supported operating system version.