CVE-2010-3849 in Linux
Summary
by MITRE
The econet_sendmsg function in net/econet/af_econet.c in the Linux kernel before 2.6.36.2, when an econet address is configured, allows local users to cause a denial of service (NULL pointer dereference and OOPS) via a sendmsg call that specifies a NULL value for the remote address field.
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Analysis
by VulDB Data Team • 11/21/2024
The CVE-2010-3849 vulnerability represents a critical denial of service flaw within the Linux kernel's econet networking implementation. This vulnerability specifically affects the econet_sendmsg function located in the net/econet/af_econet.c file, which handles the sending of messages over the econet network protocol. The econet protocol, originally developed by Acorn Computers for their Archimedes systems, was designed for small local networks and is rarely encountered in modern deployments, yet its inclusion in the Linux kernel base creates potential risks for systems that may still utilize this legacy networking protocol.
The technical flaw stems from insufficient input validation within the econet_sendmsg function where the kernel fails to properly handle NULL values in the remote address field during sendmsg system calls. When a local user process attempts to send a message through the econet protocol with a NULL remote address, the kernel's networking subsystem does not validate this input before proceeding with the message transmission logic. This lack of validation results in a NULL pointer dereference condition, where the kernel attempts to access memory at address zero or an invalid memory location. The consequence of this flaw is an immediate system crash manifesting as an OOPS (Oops error) message, which is the Linux kernel's way of reporting a critical internal error and typically leads to system instability and potential complete system shutdown.
The operational impact of this vulnerability extends beyond simple denial of service, as it can be exploited by any local user with access to the system, making it particularly dangerous in multi-user environments or systems where privilege escalation is possible. The vulnerability's exploitation requires minimal privileges and can be executed through standard user-space programs that make sendmsg calls with malformed econet addresses. This makes it an attractive target for malicious actors seeking to disrupt system availability, as the attack vector is both accessible and reliable. The vulnerability affects all Linux kernel versions prior to 2.6.36.2, representing a significant window of affected systems that would have required immediate patching to prevent exploitation. The flaw aligns with CWE-476 which describes NULL pointer dereference vulnerabilities, and can be categorized under the ATT&CK technique T1499.004 for Network Denial of Service, demonstrating how kernel-level vulnerabilities can be leveraged for system disruption attacks. The vulnerability's persistence across multiple kernel releases highlights the importance of thorough input validation in kernel space code and underscores the need for comprehensive security testing of legacy networking protocols that remain integrated into modern operating systems.
Mitigation strategies for CVE-2010-3849 primarily involve applying the official kernel patches released by the Linux kernel development team, which include proper NULL pointer checks in the econet_sendmsg function. System administrators should prioritize updating their kernel versions to 2.6.36.2 or later, as this vulnerability has been fully addressed through these patches. Organizations should also consider disabling the econet networking protocol entirely if it is not actively used within their infrastructure, as this provides an additional layer of defense against exploitation. Monitoring systems should be configured to detect unusual patterns of system crashes or OOPS messages that might indicate exploitation attempts, while network segmentation can help limit the potential impact if the vulnerability is successfully exploited. The vulnerability serves as a reminder of the critical importance of input validation in kernel space code and demonstrates how even legacy protocols can pose significant security risks when not properly secured against malformed inputs.