CVE-2017-18198 in libcdio
Summary
by MITRE
print_iso9660_recurse in iso-info.c in GNU libcdio before 1.0.0 allows remote attackers to cause a denial of service (heap-based buffer over-read) or possibly have unspecified other impact via a crafted iso file.
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Analysis
by VulDB Data Team • 02/10/2023
The vulnerability identified as CVE-2017-18198 resides within the GNU libcdio library, specifically in the print_iso9660_recurse function located in iso-info.c. This flaw represents a heap-based buffer over-read condition that can be exploited by remote attackers through the careful crafting of iso file structures. The vulnerability affects versions of GNU libcdio prior to 1.0.0, making it a significant concern for systems that rely on this library for handling iso filesystem operations. The issue stems from inadequate input validation and bounds checking when processing iso9660 filesystem structures, particularly during recursive traversal operations that occur when examining iso file metadata.
The technical implementation of this vulnerability involves the manipulation of iso file headers and directory structures to trigger memory access violations beyond allocated heap buffers. When the print_iso9660_recurse function processes a malformed iso file, it fails to properly validate the size and structure of directory entries, leading to buffer over-read conditions that can result in program crashes or unpredictable behavior. This type of vulnerability falls under CWE-125: "Out-of-bounds Read" and represents a classic example of improper input validation in filesystem parsing code. The attack vector is particularly concerning because it allows remote exploitation through crafted iso files that could be encountered during normal file processing operations, such as when mounting or examining iso images.
The operational impact of this vulnerability extends beyond simple denial of service, as the unspecified other impacts mentioned in the CVE description suggest potential for more severe consequences including information disclosure or code execution. Systems that process iso files from untrusted sources, such as file sharing platforms, backup systems, or media processing applications, become vulnerable to this attack. The vulnerability affects the broader ecosystem of software that depends on GNU libcdio for iso filesystem handling, potentially impacting operating systems, media players, and file management tools. From an ATT&CK framework perspective, this vulnerability maps to T1203: "Exploitation for Client Execution" and T1068: "Exploitation for Privilege Escalation" when considering the potential for privilege escalation through compromised applications.
Mitigation strategies for CVE-2017-18198 should prioritize immediate patching of affected GNU libcdio installations to version 1.0.0 or later where the buffer over-read protections have been implemented. Organizations should also implement strict input validation for iso file processing, including the use of sandboxed environments when handling untrusted iso content. Network security controls such as file type filtering and content inspection can help prevent malicious iso files from reaching vulnerable systems. Additionally, regular vulnerability assessments should include checks for outdated libcdio installations, and system administrators should monitor for any unusual behavior that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of proper bounds checking in filesystem parsing code and serves as a reminder of the potential for seemingly benign file processing operations to become attack vectors in complex software ecosystems.