CVE-2010-3873 in Linux
Summary
by MITRE
The X.25 implementation in the Linux kernel before 2.6.36.2 does not properly parse facilities, which allows remote attackers to cause a denial of service (heap memory corruption and panic) or possibly have unspecified other impact via malformed (1) X25_FAC_CALLING_AE or (2) X25_FAC_CALLED_AE data, related to net/x25/x25_facilities.c and net/x25/x25_in.c, a different vulnerability than CVE-2010-4164.
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Analysis
by VulDB Data Team • 10/07/2021
The vulnerability described in CVE-2010-3873 represents a critical heap memory corruption issue within the Linux kernel's X.25 protocol implementation. This flaw exists in kernel versions prior to 2.6.36.2 and specifically affects the parsing of facilities data within the X.25 network protocol stack. The X.25 protocol, while largely obsolete in modern networking environments, remains implemented in kernel space for backward compatibility and legacy system support. The vulnerability stems from inadequate input validation and sanitization within the facilities parsing functions, particularly in the net/x25/x25_facilities.c and net/x25/x25_in.c source files. This represents a classic buffer over-read and memory corruption vulnerability that can be exploited through malformed X25_FAC_CALLING_AE or X25_FAC_CALLED_AE data structures.
The technical exploitation of this vulnerability occurs when remote attackers send specially crafted X.25 protocol packets containing malformed facilities data. The kernel's X.25 implementation fails to properly validate the length and structure of these facilities parameters, leading to heap memory corruption when processing the malformed data. This corruption can manifest as kernel panics, system crashes, or potentially more severe consequences depending on the specific memory layout and corruption patterns. The vulnerability is classified as a heap-based buffer overflow according to CWE-122, and represents a privilege escalation vector that can be exploited remotely without requiring authentication. The attack surface is particularly concerning because X.25 implementations are often present in embedded systems, industrial control systems, and legacy network infrastructure where patching may be difficult or impossible.
From an operational impact perspective, this vulnerability creates significant denial of service risks for systems running affected kernel versions. The heap corruption can lead to immediate system crashes and reboot cycles, effectively rendering network services unavailable. In environments where X.25 is used for critical infrastructure communications, this can result in substantial business disruption and potential safety hazards. The vulnerability also represents a potential information disclosure risk, as the memory corruption could expose sensitive kernel memory contents to attackers. According to ATT&CK framework, this vulnerability maps to T1499.004 (Endpoint Denial of Service) and T1068 (Exploitation for Privilege Escalation), with potential for lateral movement if systems are part of larger network infrastructures. The attack can be executed remotely over the network, making it particularly dangerous in environments where legacy X.25 services are exposed to untrusted networks.
Mitigation strategies for CVE-2010-3873 primarily focus on kernel version upgrades to 2.6.36.2 or later, which contain the necessary patches to properly validate X.25 facilities data. System administrators should also implement network segmentation to isolate legacy X.25 services from untrusted networks and consider disabling X.25 protocol support entirely if the services are not actively required. Network monitoring should be enhanced to detect malformed X.25 traffic patterns that could indicate exploitation attempts. Additionally, implementing intrusion detection systems with signature-based detection for known X.25 attack patterns can provide early warning of potential exploitation. Organizations should conduct comprehensive vulnerability assessments to identify all systems running affected kernel versions and prioritize patching based on risk exposure. The fix addresses the core issue by implementing proper bounds checking and input validation for X.25 facilities parameters, preventing the heap memory corruption that leads to system instability and potential privilege escalation.