CVE-2016-6250 in libarchive
Summary
by MITRE
Integer overflow in the ISO9660 writer in libarchive before 3.2.1 allows remote attackers to cause a denial of service (application crash) or execute arbitrary code via vectors related to verifying filename lengths when writing an ISO9660 archive, which trigger a buffer overflow.
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Analysis
by VulDB Data Team • 09/09/2022
The vulnerability identified as CVE-2016-6250 represents a critical integer overflow flaw within the ISO9660 writer component of the libarchive library version 3.2.1 and earlier. This issue arises from inadequate input validation during the processing of filename lengths when constructing ISO9660 archives, creating a pathway for malicious actors to exploit the system through carefully crafted archive files. The libarchive library serves as a fundamental component in numerous applications and systems for handling various archive formats including iso9660, tar, zip, and others, making this vulnerability particularly dangerous as it can affect a wide range of software implementations.
The technical root cause of this vulnerability lies in the improper handling of integer arithmetic during the verification process of filename lengths within ISO9660 archive creation. When the ISO9660 writer processes archive files, it performs calculations to determine the appropriate buffer sizes for storing filename information. An integer overflow occurs when the calculated buffer size exceeds the maximum value that can be represented by the integer type used in the computation, leading to a wraparound condition that results in insufficient buffer allocation. This flaw falls under the CWE-190 category of Integer Overflow or Wraparound, which is classified as a common weakness in software development practices. The vulnerability specifically manifests when the system attempts to verify filename lengths, triggering a buffer overflow condition that can be exploited to either crash the application or potentially execute arbitrary code.
The operational impact of CVE-2016-6250 extends beyond simple denial of service scenarios, as it presents a potential code execution vector that could be leveraged by remote attackers. When an application utilizing libarchive processes a maliciously crafted ISO9660 archive, the integer overflow can cause memory corruption that may be manipulated to redirect program execution flow. This vulnerability is particularly concerning because many systems and applications rely on libarchive for processing user-supplied archive files, creating numerous potential attack vectors across different software ecosystems. The attack surface includes web applications, file processing services, backup systems, and any software that handles ISO9660 format archives. The vulnerability aligns with ATT&CK technique T1203 (Exploitation for Client Execution) and T1059 (Command and Scripting Interpreter) as it enables adversaries to gain remote code execution capabilities through archive processing.
Mitigation strategies for CVE-2016-6250 should focus on immediate patching of affected libarchive installations to version 3.2.1 or later, where the integer overflow has been addressed through proper input validation and boundary checking. Organizations should implement comprehensive vulnerability management processes to identify all systems utilizing vulnerable versions of libarchive and ensure timely updates are deployed. Additional defensive measures include implementing strict input validation for all archive files processed by applications, employing sandboxing techniques for archive handling operations, and deploying network monitoring to detect suspicious archive processing activities. The fix implemented in libarchive 3.2.1 involves enhanced boundary checking and proper integer overflow protection mechanisms that prevent the wraparound conditions leading to buffer overflows. Security teams should also consider implementing application whitelisting policies to restrict execution of archive processing applications from untrusted sources and establish regular security assessments to identify potential similar vulnerabilities in other library components.