CVE-2012-6549 in Linux
Summary
by MITRE
The isofs_export_encode_fh function in fs/isofs/export.c in the Linux kernel before 3.6 does not initialize a certain structure member, which allows local users to obtain sensitive information from kernel heap memory via a crafted application.
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Analysis
by VulDB Data Team • 01/01/2022
The vulnerability identified as CVE-2012-6549 resides within the Linux kernel's isofs filesystem implementation, specifically in the isofs_export_encode_fh function located in fs/isofs/export.c. This flaw represents a classic information disclosure vulnerability that occurs due to improper memory initialization within kernel space. The vulnerability affects Linux kernel versions prior to 3.6, making it a significant concern for systems running older kernel versions where patching may not have been implemented.
The technical root cause of this vulnerability stems from the isofs_export_encode_fh function failing to properly initialize a structure member before utilizing it in the filesystem export handling process. This uninitialized memory component contains residual data from previous operations within the kernel heap, creating a potential information leak scenario. When a crafted application invokes this function through appropriate filesystem operations, the uninitialized structure member inadvertently exposes kernel heap memory contents to user-space applications, effectively leaking sensitive information that could include cryptographic keys, passwords, or other confidential data stored in kernel memory.
From an operational perspective, this vulnerability presents a local privilege escalation vector that allows attackers with user-level access to potentially extract sensitive kernel memory contents. The impact extends beyond simple information disclosure as the leaked data could contain critical system information that could be leveraged for further attacks, including but not limited to kernel exploitation techniques. Attackers could use this information to bypass security mechanisms, understand kernel memory layout, or identify other potential vulnerabilities within the system. The vulnerability operates at the kernel level, making it particularly dangerous as it can be exploited without requiring special privileges beyond normal user access.
The vulnerability aligns with CWE-457, which describes the use of uninitialized variables, and demonstrates characteristics consistent with information disclosure vulnerabilities in kernel space. According to ATT&CK framework, this vulnerability maps to T1005 (Data from Local System) and T1059 (Command and Scripting Interpreter) as attackers could use the information leakage to gather system intelligence and potentially craft more sophisticated attacks. The flaw represents a memory safety issue that could be exploited by malicious applications to extract kernel memory contents, potentially leading to privilege escalation or system compromise. Organizations should prioritize patching affected systems to address this vulnerability and implement monitoring for suspicious filesystem operations that might indicate exploitation attempts. The fix implemented in kernel version 3.6 properly initializes the affected structure member, preventing the information disclosure and ensuring that kernel heap memory contents remain protected from unauthorized access.