CVE-2011-1173 in Linux
Summary
by MITRE
The econet_sendmsg function in net/econet/af_econet.c in the Linux kernel before 2.6.39 on the x86_64 platform allows remote attackers to obtain potentially sensitive information from kernel stack memory by reading uninitialized data in the ah field of an Acorn Universal Networking (AUN) packet.
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Analysis
by VulDB Data Team • 11/13/2021
The vulnerability identified as CVE-2011-1173 represents a classic information disclosure flaw within the Linux kernel's networking stack, specifically affecting the econet subsystem. This issue manifests in the econet_sendmsg function located in the net/econet/af_econet.c source file, which handles the sending of messages through the Acorn Universal Networking protocol implementation. The vulnerability is particularly significant because it affects systems running Linux kernel versions prior to 2.6.39, with the x86_64 platform being explicitly mentioned as a vulnerable architecture, indicating that the flaw may have been exacerbated by specific 64-bit memory handling characteristics.
The technical root cause of this vulnerability stems from the improper initialization of memory structures within the AUN packet handling mechanism. Specifically, when processing packets through the econet_sendmsg function, the ah field of an Acorn Universal Networking packet remains uninitialized, creating a situation where sensitive data from the kernel stack could be inadvertently exposed to remote attackers. This uninitialized data typically includes remnants of previous kernel operations, including potentially sensitive information such as cryptographic keys, session tokens, or other confidential data that may have been stored in the same memory locations. The flaw operates under CWE-248, which classifies it as an "Uncaught Exception" that leads to information exposure through uninitialized memory, making it a direct descendant of the broader category of memory safety issues.
The operational impact of this vulnerability extends beyond simple information disclosure, as remote attackers can leverage this flaw to gain potentially sensitive information that could be used in subsequent attacks. The ability to read uninitialized kernel stack memory means that an attacker could potentially extract confidential data that was previously stored in those memory locations, including but not limited to system credentials, encryption keys, or other system-specific information that could compromise the overall security posture. This vulnerability aligns with ATT&CK technique T1005, which involves data from local system, and demonstrates how seemingly benign network protocols can become attack vectors when proper memory initialization practices are not followed. The impact is particularly concerning for systems that rely on the econet networking protocol for communication, as it could enable attackers to gather intelligence about the internal workings of the system or extract sensitive information that could be used for privilege escalation or lateral movement within a network.
Mitigation strategies for CVE-2011-1173 primarily focus on upgrading to Linux kernel versions 2.6.39 or later, where the issue has been resolved through proper memory initialization practices. System administrators should prioritize patching affected systems, especially those running older kernel versions that may be exposed to remote network attacks. Additionally, network segmentation and firewall rules can be implemented to limit access to systems that may be vulnerable, reducing the attack surface for potential exploitation. The fix implemented in the patched kernel versions typically involves ensuring that all packet fields are properly initialized before processing, which prevents the leakage of uninitialized stack data. Organizations should also conduct thorough vulnerability assessments to identify systems running vulnerable kernel versions and establish monitoring procedures to detect potential exploitation attempts. This vulnerability serves as a reminder of the critical importance of memory safety practices in kernel development and the potential security implications of seemingly minor initialization oversights in system-level code.