Source: cve@mitre.org
Signed integer overflow in the bttv_read function in the bttv driver (bttv-driver.c) in Linux kernel before 2.4.20 has unknown impact and attack vectors.
A critical integer overflow vulnerability exists in the bttv driver of older Linux kernels, potentially allowing an attacker to execute arbitrary code. This flaw, stemming from an arithmetic error within the bttv_read function, could lead to system compromise and data exfiltration. Successful exploitation could result in a complete takeover of the affected system.
Step 1: Triggering the Vulnerability: An attacker crafts a malicious request to the bttv driver, likely through a device file associated with the bttv driver (e.g., /dev/bttv0). This request includes specific parameters that influence the bttv_read function's calculations.
Step 2: Integer Overflow: The crafted parameters cause an integer overflow within the bttv_read function when calculating memory offsets or buffer sizes. This results in a negative value.
Step 3: Memory Corruption: The negative value, now interpreted as a large positive value due to the signed integer representation, is used in memory operations. This could lead to writing outside of allocated buffers, overwriting critical data structures, or other memory corruption.
Step 4: Code Execution: By carefully crafting the input, the attacker can overwrite critical data structures, such as function pointers or control data, to redirect program execution to attacker-controlled code. This could involve overwriting the return address on the stack or hijacking a function pointer.
Step 5: Privilege Escalation: The attacker's code, now running with kernel privileges, can execute arbitrary commands, potentially leading to a complete system compromise, including privilege escalation and data exfiltration.
The vulnerability lies within the bttv_read function of the bttv driver (bttv-driver.c) in Linux kernels prior to version 2.4.20. Specifically, a signed integer overflow occurs during the calculation of buffer sizes or offsets when handling video data. The bttv_read function likely uses a signed integer to calculate the amount of data to read. By providing a crafted input, an attacker can cause this integer to overflow, resulting in a negative value. This negative value is then used in subsequent memory operations, such as memory allocation or data copying. This can lead to a buffer overflow or other memory corruption issues. The exact details of the overflow (e.g., which variables are involved, the specific arithmetic operations) are not fully detailed in the CVE description, but the core issue is the incorrect handling of integer arithmetic, leading to a potential heap overflow or stack overflow depending on the context.
While no specific APTs are directly linked to this CVE, the vulnerability's potential for remote code execution makes it attractive to various threat actors. Given the age of the vulnerability, it's less likely to be actively targeted by sophisticated APTs, but it could be used in conjunction with other vulnerabilities in a multi-stage attack. CISA KEV status: Not Listed.
Monitor system logs for unusual activity related to the bttv driver (e.g., errors, crashes, unexpected access attempts).
Analyze kernel crash dumps for signs of memory corruption, such as overwritten data structures or unexpected code execution.
Network traffic analysis for any unusual communication patterns originating from the affected system, especially if the system is not expected to be communicating with the outside world.
Use kernel debugging tools (e.g., kprobe, ftrace) to monitor the execution of the bttv_read function and identify suspicious parameter values or memory access patterns.
Implement host-based intrusion detection systems (HIDS) to monitor for suspicious file modifications or process behavior related to the bttv driver.
Upgrade the Linux kernel to version 2.4.20 or later. This is the primary and most effective remediation step.
If upgrading is not immediately possible, consider disabling the bttv driver if it is not required for system functionality. This mitigates the attack surface.
Implement robust input validation for any user-supplied data that is passed to the bttv driver, even if the driver is not directly exposed to the user. This can help prevent the integer overflow.
Apply kernel security hardening measures, such as address space layout randomization (ASLR) and kernel address space protection (KASLR), to make exploitation more difficult.
Regularly scan systems for vulnerabilities using vulnerability scanners.
Implement a strong patch management process to ensure that security updates are applied promptly.