CVE-2013-3237 in Linux
Summary
by MITRE
The vsock_stream_sendmsg function in net/vmw_vsock/af_vsock.c in the Linux kernel before 3.9-rc7 does not initialize a certain length variable, which allows local users to obtain sensitive information from kernel stack memory via a crafted recvmsg or recvfrom system call.
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Analysis
by VulDB Data Team • 05/11/2017
The vulnerability identified as CVE-2013-3237 resides within the Linux kernel's virtual socket implementation, specifically in the vsock_stream_sendmsg function located at net/vmw_vsock/af_vsock.c. This flaw represents a classic case of uninitialized variable usage that can lead to information disclosure, making it particularly concerning for systems running vulnerable kernel versions prior to 3.9-rc7. The vulnerability affects the VMware vSocket (virtual socket) subsystem which provides communication channels between guest operating systems and hypervisors in virtualized environments.
The technical root cause of this vulnerability stems from the improper initialization of a length variable within the vsock_stream_sendmsg function. When processing socket communication, the function fails to properly initialize a critical length parameter before using it in subsequent operations. This uninitialized variable can contain residual data from previous operations or memory contents, creating a potential information leak scenario. The vulnerability is triggered when local users execute crafted recvmsg or recvfrom system calls against vsocket connections, allowing them to indirectly access kernel stack memory through the improperly initialized variable.
From an operational perspective, this vulnerability presents a significant risk to systems utilizing VMware virtualization environments where vsocket communication is active. Local attackers who can execute code on the target system can leverage this flaw to extract sensitive information from kernel memory, potentially including cryptographic keys, session tokens, or other confidential data. The impact extends beyond simple information disclosure as this leaked memory could contain credentials, system configuration details, or other sensitive data that could be exploited for privilege escalation or further attacks. The vulnerability is particularly dangerous in environments where multiple virtual machines share the same host system, as it could enable cross-vm information leakage.
The security implications of this vulnerability align with CWE-457: Use of Uninitialized Variable, which classifies this issue as a fundamental programming error that can lead to unpredictable behavior and information disclosure. From an ATT&CK framework perspective, this vulnerability maps to T1005: Data from Local System and T1059: Command and Scripting Interpreter, as it enables local information gathering and could facilitate further exploitation. The attack vector requires local system access, making it a local privilege escalation or information disclosure vulnerability rather than a remote attack. Organizations should prioritize patching systems running kernel versions before 3.9-rc7 to prevent exploitation of this vulnerability. The fix involves properly initializing the length variable in the vsock_stream_sendmsg function to ensure that no residual data is used in kernel memory operations, thereby preventing the information disclosure that occurs when uninitialized variables are accessed.