Source: cve@mitre.org
Unspecified vulnerability in the pcilynx ieee1394 firewire driver (pcilynx.c) in Linux kernel before 2.4.20 has unknown impact and attack vectors, related to "wrap handling."
Critical vulnerability exists in the Linux kernel's FireWire driver (pcilynx.c), potentially allowing for remote code execution or denial-of-service. The vulnerability stems from improper handling of data wrapping within the driver, enabling attackers to manipulate memory and potentially gain unauthorized access to the system.
Step 1: FireWire Device Connection: The attacker must have physical access to the target system or be able to connect to the FireWire bus remotely (e.g., through a network-attached FireWire device).
Step 2: Malformed FireWire Packet Crafting: The attacker crafts a malicious FireWire packet designed to exploit the "wrap handling" vulnerability. This packet likely contains carefully crafted data that, when processed by the pcilynx.c driver, triggers the memory corruption.
Step 3: Packet Injection: The attacker sends the malicious FireWire packet to the target system.
Step 4: Driver Processing: The pcilynx.c driver receives and processes the malicious packet.
Step 5: Memory Corruption: Due to the "wrap handling" flaw, the driver incorrectly calculates memory offsets or sizes, leading to a buffer overflow or other memory corruption.
Step 6: Code Execution/DoS: The memory corruption overwrites critical kernel data structures, potentially allowing the attacker to execute arbitrary code with kernel privileges (remote code execution) or causing a system crash (denial-of-service).
The vulnerability lies within the pcilynx.c driver, specifically in its handling of FireWire data transfers. The description mentions "wrap handling," suggesting a flaw in how the driver manages data that wraps around memory boundaries. This could involve an integer overflow, leading to an out-of-bounds write, or a logic error that allows for the corruption of kernel memory. The lack of specific details in the CVE makes pinpointing the exact root cause difficult without further reverse engineering or access to the vulnerable source code. However, the phrase "wrap handling" strongly suggests a potential buffer overflow or other memory corruption issue related to how the driver calculates memory offsets or sizes during FireWire data transfers. The vulnerability likely allows an attacker to overwrite critical kernel data structures, leading to a system crash (DoS) or, more critically, the ability to execute arbitrary code with kernel privileges.
Given the age and nature of the vulnerability, it is unlikely to be actively targeted by sophisticated APTs. However, it could be exploited by less skilled attackers or incorporated into malware targeting older systems. The vulnerability is not listed on the CISA KEV list, but it's critical to note that the absence of a KEV listing does not mean a vulnerability is not exploitable. The potential for remote code execution makes this a high-impact vulnerability.
Monitor FireWire bus traffic for unusual packet sizes or patterns, especially those involving large data transfers or unusual addressing schemes.
Analyze system logs for kernel panics or unexpected errors related to the FireWire driver (pcilynx.c).
Implement host-based intrusion detection systems (HIDS) to monitor for suspicious file modifications or process behavior.
Examine memory dumps (if available after a crash) for signs of memory corruption within the FireWire driver's data structures.
Network Intrusion Detection Systems (NIDS) can be configured to detect malicious FireWire packets, if the network configuration allows for FireWire traffic to be monitored.
Upgrade the Linux kernel to version 2.4.20 or later. This is the most direct and effective remediation.
Disable the FireWire driver (pcilynx) if it is not required. This eliminates the attack surface.
Implement strict input validation on all FireWire data to prevent malformed packets from reaching the vulnerable driver.
Apply kernel security hardening measures, such as address space layout randomization (ASLR) and kernel address space protection (KASLR), to mitigate the impact of potential exploits.
Regularly scan systems for known vulnerabilities using vulnerability scanners.
Implement a robust patch management process to ensure timely application of security updates.