CVE-2010-4342 in Linux
Summary
by MITRE
The aun_incoming function in net/econet/af_econet.c in the Linux kernel before 2.6.37-rc6, when Econet is enabled, allows remote attackers to cause a denial of service (NULL pointer dereference and OOPS) by sending an Acorn Universal Networking (AUN) packet over UDP.
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Analysis
by VulDB Data Team • 10/07/2021
The vulnerability described in CVE-2010-4342 represents a critical null pointer dereference flaw within the Linux kernel's Econet networking implementation. This issue exists in the aun_incoming function located in net/econet/af_econet.c, affecting Linux kernel versions prior to 2.6.37-rc6 where Econet networking support is enabled. The flaw specifically manifests when the kernel processes Acorn Universal Networking packets transmitted over User Datagram Protocol, creating a pathway for remote attackers to exploit the system's networking stack. The vulnerability operates at the kernel level, making it particularly dangerous as it can be triggered without local access and potentially lead to complete system instability.
The technical exploitation of this vulnerability occurs through the improper handling of incoming AUN packets that lack proper validation before being processed by the aun_incoming function. When such malformed packets are received, the function attempts to dereference a null pointer reference, causing an immediate kernel panic and system crash. This type of vulnerability falls under CWE-476, which specifically addresses null pointer dereference conditions in software implementations. The OOPS message generated by the kernel indicates a kernel bug that results in the system becoming unresponsive, effectively creating a denial of service condition that can be easily triggered by remote attackers without requiring any authentication or privileged access.
The operational impact of this vulnerability extends beyond simple service disruption as it represents a fundamental flaw in the kernel's network packet handling mechanism. Attackers can reliably cause system crashes by sending carefully crafted UDP packets to systems running vulnerable kernel versions, potentially leading to extended downtime and service unavailability. This vulnerability particularly affects systems that have Econet networking support enabled, which historically includes certain embedded systems and legacy networking equipment that may still be in operation. The attack vector is particularly concerning because it can be executed remotely over the network, making it applicable to a wide range of target systems without requiring physical access or local privileges. The vulnerability demonstrates a clear weakness in input validation and error handling within kernel networking code, aligning with ATT&CK technique T1499.002 which covers network denial of service attacks.
Mitigation strategies for CVE-2010-4342 primarily involve upgrading to Linux kernel version 2.6.37-rc6 or later, which contains the necessary patches to address the null pointer dereference issue. System administrators should also consider disabling Econet networking support entirely if the functionality is not required, as this eliminates the attack surface associated with this vulnerable code path. Network segmentation and firewall rules can be implemented to restrict UDP traffic on ports associated with Econet protocols, although this approach provides only partial protection since the vulnerability can be triggered by any properly formatted AUN packet. Organizations should also implement monitoring solutions to detect unusual network traffic patterns that might indicate exploitation attempts, as the kernel OOPS messages generated by the vulnerability can serve as clear indicators of successful attacks. The fix implemented in the patched kernel versions ensures proper validation of incoming AUN packets and includes appropriate error handling to prevent null pointer dereference conditions, thereby maintaining system stability and preventing unauthorized denial of service attacks.