CVE-2010-3848 in Linux
Summary
by MITRE
Stack-based buffer overflow in 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 gain privileges by providing a large number of iovec structures.
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Analysis
by VulDB Data Team • 06/22/2024
The vulnerability identified as CVE-2010-3848 represents a critical stack-based buffer overflow within the Linux kernel's econet networking subsystem. This flaw exists in the econet_sendmsg function located in net/econet/af_econet.c file and affects kernel versions prior to 2.6.36.2. The econet protocol, originally developed by Acorn Computers for their Archimedes range of computers, was designed to provide a simple and efficient local area network solution that has since been integrated into the Linux kernel for backward compatibility. The vulnerability manifests when the kernel processes econet addresses and handles a large number of iovec structures, which are used to describe scatter-gather memory regions for network operations.
The technical implementation of this vulnerability stems from improper bounds checking within the econet_sendmsg function where the kernel fails to adequately validate the number of iovec structures provided by a user-space process. When a local user submits an excessive number of iovec entries, the kernel's stack buffer allocation does not properly account for the actual memory requirements, leading to a classic stack overflow condition. This overflow occurs because the kernel's handling of the econet address structure does not enforce reasonable limits on the number of iovec entries that can be processed in a single operation. The flaw is particularly dangerous as it allows privilege escalation from a local user to root access, since the kernel's security model relies on proper input validation to prevent unauthorized access to kernel memory spaces.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and denial of service conditions. A local attacker with minimal privileges can exploit this vulnerability to execute arbitrary code with kernel-level privileges, effectively bypassing all kernel security mechanisms including access controls, memory protection, and privilege separation. This type of vulnerability is classified as a CWE-121 stack-based buffer overflow, which directly maps to the ATT&CK technique T1068 Privilege Escalation through exploitation of kernel vulnerabilities. The vulnerability can be exploited by any local user who has the ability to execute code on the target system, making it particularly concerning in multi-user environments where privilege separation is essential for system security. The impact is amplified because the kernel is running with the highest privileges, meaning successful exploitation results in complete system compromise.
Mitigation strategies for CVE-2010-3848 primarily focus on immediate kernel updates to versions 2.6.36.2 or later where the vulnerability has been patched. The fix implemented by the Linux kernel development team involved adding proper bounds checking to validate the number of iovec structures before processing them, ensuring that the kernel does not allocate excessive stack space for the econet address handling. Additionally, system administrators should consider disabling the econet protocol entirely if it is not required for system operations, as this eliminates the attack surface entirely. The patch demonstrates the importance of proper input validation and bounds checking in kernel space operations, aligning with security best practices outlined in the CERT/CC Secure Coding Standards. Organizations should also implement monitoring for suspicious network activity and ensure that all systems are maintained with current security patches to prevent exploitation of similar kernel vulnerabilities. The vulnerability serves as a reminder of the critical importance of kernel security testing and the potential for privilege escalation vulnerabilities to result in complete system compromise when not properly addressed through defensive programming practices.