Multiple buffer overflows in HP Tru64 UNIX 5.x allow local users to execute arbitrary code via (1) a long -contextDir argument to dtaction, (2) a long -p argument to dtprintinfo, (3) a long -customization argument to dxterm, or (4) a long DISPLAY environment variable to dtterm.
HP Tru64 UNIX 5.x systems are vulnerable to multiple buffer overflow vulnerabilities, allowing local users to execute arbitrary code. Exploitation of these flaws can lead to complete system compromise, granting attackers elevated privileges and control over the affected server. This poses a significant risk to confidentiality, integrity, and availability of critical data and services.
Step 1: Target Selection: The attacker identifies a vulnerable HP Tru64 UNIX 5.x system.
Step 2: Vulnerability Identification: The attacker determines which vulnerable utility (dtaction, dtprintinfo, dxterm, or dtterm) is accessible and exploitable.
Step 3: Payload Delivery: The attacker crafts a malicious input string exceeding the buffer size of the targeted utility's vulnerable argument (e.g., -contextDir for dtaction, -p for dtprintinfo, -customization for dxterm, or the DISPLAY environment variable for dtterm). This input includes shellcode designed to execute arbitrary commands.
Step 4: Buffer Overflow Trigger: The attacker executes the vulnerable utility with the crafted payload. This causes a buffer overflow, overwriting adjacent memory on the stack.
Step 5: Control Hijack: The overflow overwrites the return address of the function. The attacker's crafted payload includes the address of the shellcode.
Step 6: Code Execution: When the function returns, control is transferred to the attacker's shellcode, which executes with the privileges of the vulnerable process (typically the user running the command).
Step 7: Privilege Escalation (Optional): The attacker's shellcode can then be used to escalate privileges, potentially gaining root access to the system.
The root cause of these vulnerabilities lies in the lack of proper bounds checking when handling user-supplied input in several HP Tru64 UNIX utilities. Specifically, the dtaction, dtprintinfo, dxterm, and dtterm utilities fail to validate the length of input arguments and environment variables. This allows an attacker to provide excessively long strings, overflowing the allocated buffers on the stack. This buffer overflow overwrites adjacent memory, including critical control data like the return address. By carefully crafting the malicious input, an attacker can overwrite the return address with the address of their injected shellcode, leading to arbitrary code execution with the privileges of the vulnerable process. The lack of input validation and memory management are the core flaws.