CVE-2005-1260 in bzip2
Summary
by MITRE
bzip2 allows remote attackers to cause a denial of service (hard drive consumption) via a crafted bzip2 file that causes an infinite loop (a.k.a "decompression bomb").
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Analysis
by VulDB Data Team • 03/11/2021
The vulnerability identified as CVE-2005-1260 represents a critical denial of service flaw in the bzip2 compression utility that has significant implications for system security and resource management. This vulnerability specifically affects the decompression process of bzip2 files, where maliciously crafted archives can trigger infinite loops during decompression operations. The flaw manifests when the compression utility encounters specially constructed bzip2 files that contain recursive or self-referential data structures designed to exploit the decompression algorithm's handling of compressed data streams.
The technical implementation of this vulnerability stems from the bzip2 decompression algorithm's insufficient validation of input data structures. When processing malformed bzip2 files, the decompression routine enters into an infinite loop where it repeatedly processes the same data segments without making progress toward decompressing the actual content. This occurs because the algorithm fails to properly detect and terminate when encountering data patterns that would naturally lead to infinite recursion or loop conditions during the decompression phase. The vulnerability is classified under CWE-121 as a buffer overflow condition, though more specifically it represents a resource exhaustion attack vector that consumes system resources without proper bounds checking.
From an operational perspective, this vulnerability presents a substantial risk to systems that process untrusted bzip2 files, particularly those that automatically decompress files from external sources or user uploads. The attack scenario involves an adversary crafting a malicious bzip2 file that appears legitimate but contains recursive data structures designed to trigger the infinite loop condition. When such a file is processed by a vulnerable bzip2 utility, the system's hard drive space becomes consumed rapidly as the decompression process continues indefinitely, potentially leading to complete system failure or denial of service for legitimate users. The impact extends beyond simple resource exhaustion as it can also cause system instability and may be exploited in larger attack chains targeting system availability.
The attack vector for CVE-2005-1260 aligns with techniques described in the MITRE ATT&CK framework under the Tactic of Resource Exhaustion and Denial of Service. Systems that automatically decompress files, such as web applications processing user uploads, email servers handling compressed attachments, or automated backup systems, become vulnerable to this attack. The vulnerability can be particularly dangerous in environments where bzip2 is used in automated processing pipelines or where system administrators have not implemented proper input validation and resource limits. Security practitioners should consider this vulnerability when evaluating system resilience against resource exhaustion attacks and implementing proper decompression safeguards.
Effective mitigation strategies for CVE-2005-1260 involve multiple layers of defense including immediate software updates to patched versions of bzip2 that implement proper bounds checking and loop detection mechanisms. System administrators should implement resource limits and timeouts for decompression operations to prevent indefinite processing of potentially malicious files. Input validation should be implemented at all stages where bzip2 files are processed, including size limits and content verification before decompression. The implementation of proper decompression sandboxes or containerized environments can isolate the decompression process and limit potential damage from resource exhaustion attacks. Additionally, monitoring systems should be configured to detect unusual resource consumption patterns that may indicate exploitation attempts. Organizations should also consider implementing automated scanning for known malicious patterns in compressed files and maintain updated threat intelligence feeds to identify potential variants of this attack vector.