CVE-2005-2459 in Linux
Summary
by MITRE
The huft_build function in inflate.c in the zlib routines in the Linux kernel before 2.6.12.5 returns the wrong value, which allows remote attackers to cause a denial of service (kernel crash) via a certain compressed file that leads to a null pointer dereference, a different vulnerbility than CVE-2005-2458.
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Analysis
by VulDB Data Team • 08/02/2019
The vulnerability identified as CVE-2005-2459 represents a critical flaw in the Linux kernel's compression handling mechanism that specifically affects the zlib routines used for decompressing data. This issue resides within the huft_build function located in the inflate.c file, which is part of the kernel's decompression infrastructure. The flaw manifests when processing certain malformed compressed files that trigger an improper return value from the function, creating a pathway for malicious actors to exploit the system's decompression logic. The vulnerability operates at the kernel level, making it particularly dangerous as it can be leveraged to cause system-wide disruptions without requiring elevated privileges or direct user interaction.
The technical implementation of this vulnerability stems from a fundamental error in the decompression algorithm's control flow management. When the huft_build function encounters specific patterns in compressed data, it fails to properly validate the return values from internal operations, leading to a situation where a null pointer is dereferenced during the decompression process. This null pointer dereference occurs because the function returns an incorrect value that subsequently causes the kernel to attempt accessing memory locations that have not been properly allocated or initialized. The flaw is particularly insidious because it does not require complex exploitation techniques or specialized knowledge of kernel internals, making it accessible to attackers with basic understanding of compressed data formats.
The operational impact of this vulnerability extends beyond simple denial of service, as it can lead to complete system crashes and potential data loss in environments where compressed data processing is common. Systems running Linux kernels version 2.6.12.4 and earlier are susceptible to this attack vector, particularly those that process untrusted compressed data from network sources, file uploads, or decompression of external storage media. The vulnerability can be triggered through various attack vectors including network-based protocols that utilize compression, file system operations involving compressed archives, or any mechanism that relies on the kernel's zlib decompression routines. The resulting kernel crash typically manifests as an immediate system halt or reboot, disrupting services and potentially causing data corruption if the crash occurs during critical operations.
Mitigation strategies for CVE-2005-2459 primarily focus on kernel version updates and patching procedures that address the specific return value handling in the huft_build function. System administrators should immediately upgrade to Linux kernel versions 2.6.12.5 or later, where the vulnerability has been resolved through proper validation of return values and null pointer checks. Additional protective measures include implementing strict input validation for compressed data sources, deploying network filtering rules to block suspicious compressed file transfers, and establishing monitoring systems to detect unusual decompression activity that might indicate exploitation attempts. The vulnerability aligns with CWE-476 which describes null pointer dereference conditions, and represents a classic example of how improper error handling in cryptographic and compression algorithms can lead to system instability. From an ATT&CK perspective, this vulnerability maps to the privilege escalation and denial of service tactics, as attackers can leverage it to disrupt system availability without requiring direct access to system resources. Organizations should also consider implementing kernel hardening measures and runtime protection mechanisms that can detect and prevent exploitation attempts targeting known kernel vulnerabilities.