CVE-2007-3644 in libarchive
Summary
by MITRE
archive_read_support_format_tar.c in libarchive before 2.2.4 allows user-assisted remote attackers to cause a denial of service (infinite loop) via (1) an end-of-file condition within a pax extension header or (2) a malformed pax extension header in an (a) PAX or a (b) TAR archive.
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Analysis
by VulDB Data Team • 11/27/2024
The vulnerability described in CVE-2007-3644 affects the libarchive library version 2.2.3 and earlier, specifically within the archive_read_support_format_tar.c module responsible for processing tar archive formats. This issue represents a classic denial of service vulnerability that can be exploited by remote attackers who have the ability to provide maliciously crafted archive files to systems using vulnerable libarchive implementations. The flaw manifests when the library encounters specific malformed pax extension headers within tar archives, creating conditions that lead to infinite loop execution patterns that consume excessive system resources and ultimately render the targeted service unavailable.
The technical implementation of this vulnerability involves two distinct attack vectors that exploit different aspects of the pax extension header processing logic. The first vector occurs when an end-of-file condition appears within a pax extension header, causing the parser to enter an infinite loop while attempting to process incomplete data structures. The second vector involves malformed pax extension headers that contain invalid or corrupted data structures which the parser cannot properly handle, leading to similar infinite loop conditions. Both scenarios exploit the library's failure to properly validate input data structures before attempting to parse them, particularly in the context of extended pax headers that provide additional metadata about archive entries. This vulnerability falls under the CWE-835 category of infinite loops, where the loop condition is never properly terminated due to inadequate input validation or error handling mechanisms.
From an operational impact perspective, this vulnerability can be particularly dangerous in environments where systems automatically process user-uploaded archives or download archives from untrusted sources. The infinite loop condition consumes CPU resources indefinitely, potentially leading to system performance degradation, service unavailability, or even complete system crashes in resource-constrained environments. Attackers can leverage this vulnerability to perform resource exhaustion attacks against web servers, file processing services, or any application that relies on libarchive for archive handling. The vulnerability is particularly concerning because it can be triggered remotely without requiring authentication or special privileges, making it an attractive target for automated exploitation campaigns. This type of vulnerability aligns with ATT&CK technique T1499.004 for resource exhaustion attacks, where adversaries consume system resources to deny service to legitimate users.
The mitigation strategy for this vulnerability involves upgrading to libarchive version 2.2.4 or later, where the parsing logic has been corrected to properly handle malformed pax extension headers and end-of-file conditions. System administrators should also implement input validation and sanitization measures at the application level, particularly when processing user-supplied archive files. Additional protective measures include implementing timeouts for archive processing operations, monitoring for unusual CPU usage patterns, and deploying network-based intrusion detection systems to identify potential exploitation attempts. Organizations should also consider implementing sandboxing or containerization techniques when processing untrusted archive files to limit the potential impact of successful exploitation attempts. The fix implemented in version 2.2.4 addresses the core parsing logic by adding proper boundary checks and error handling for pax extension header processing, preventing the infinite loop conditions that previously occurred when encountering malformed data structures.