Source: cve@mitre.org
Multiple buffer overflows in QNX 4.25 may allow local users to execute arbitrary code via long command line arguments to (1) sample, (2) ex, (3) du, (4) find, (5) lex, (6) mkdir, (7) rm, (8) serserv, (9) tcpserv, (10) termdef, (11) time, (12) unzip, (13) use, (14) wcc, (15) wcc386, (16) wd, (17) wdisasm, (18) which, (19) wlib, (20) wlink, (21) wpp, (22) wpp386, (23) wprof, (24) write, or (25) wstrip.
Multiple buffer overflows in QNX 4.25 allow local users to execute arbitrary code, posing a significant risk of system compromise. Exploiting these vulnerabilities grants attackers the ability to execute malicious code with the privileges of the vulnerable process, potentially leading to complete system takeover and data exfiltration.
Step 1: Input Preparation: The attacker crafts a malicious command-line argument that is significantly longer than the expected input size for a vulnerable utility (e.g., sample, ex, du, etc.).
Step 2: Payload Insertion: The crafted input includes shellcode designed to execute arbitrary commands, often to gain a reverse shell or escalate privileges.
Step 3: Vulnerability Trigger: The attacker executes the vulnerable utility with the malicious command-line argument. This can be done directly or indirectly through other processes.
Step 4: Buffer Overflow: The excessively long argument overflows the allocated buffer within the vulnerable utility's memory space.
Step 5: Control Hijack: The overflow overwrites critical memory regions, including the return address on the stack. The return address is overwritten with the address of the attacker's shellcode.
Step 6: Code Execution: When the vulnerable function returns, control is transferred to the attacker's shellcode, which executes with the privileges of the vulnerable process.
The vulnerability stems from a buffer overflow condition within numerous command-line utilities in QNX 4.25. These utilities fail to properly validate the size of command-line arguments, leading to an overflow when a sufficiently long input is provided. Specifically, the vulnerable code allocates a fixed-size buffer on the stack to store the command-line arguments. When an argument exceeds the allocated buffer size, it overwrites adjacent memory locations, including potentially the return address. By crafting a malicious input, an attacker can overwrite the return address with the address of their injected shellcode, causing the program to execute the attacker's code upon return from the vulnerable function. The root cause is a lack of bounds checking on input arguments and insufficient memory management.
Due to the age of the vulnerability, it is unlikely to be actively targeted by sophisticated APTs. However, it could be leveraged by less sophisticated actors or used as part of a broader attack chain. The vulnerability is not listed in the CISA KEV.
Monitor system logs for unusually long command-line arguments passed to the vulnerable utilities (e.g., sample, ex, du, etc.).
Analyze process memory dumps for evidence of stack corruption or shellcode injection.
Network traffic analysis for suspicious outbound connections originating from systems running QNX 4.25, indicating potential command-and-control activity after exploitation.
File integrity monitoring to detect changes to system binaries or the creation of new malicious files.
Upgrade to a supported and patched version of QNX. QNX 6.x and later versions are recommended.
If upgrading is not possible, apply any available patches or security updates for QNX 4.25 (though these are unlikely to exist).
Implement strict input validation on all command-line arguments, even if the system is considered 'isolated'.
Restrict access to the vulnerable utilities. Limit the users and processes that can execute these commands.
Implement a host-based intrusion detection system (HIDS) to monitor for suspicious activity, such as shellcode execution or unexpected process behavior.
Consider using a memory protection scheme, if available, to prevent execution of code from the stack.