CVE-2017-12144 in ytnef
Summary
by MITRE
In ytnef 1.9.2, an allocation failure was found in the function TNEFFillMapi in ytnef.c, which allows attackers to cause a denial of service via a crafted file.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 12/14/2022
The vulnerability identified as CVE-2017-12144 represents a critical denial of service condition within the ytnef library version 1.9.2. This library serves as a TNEF (Transport Neutral Encapsulation Format) parser designed to handle Microsoft Outlook email attachments that are encoded in TNEF format. The flaw manifests in the TNEFFillMapi function located within the ytnef.c source file, where improper memory allocation handling creates a path for malicious actors to exploit the system's resource management mechanisms.
The technical nature of this vulnerability stems from an allocation failure that occurs during the processing of malformed TNEF files. When the TNEFFillMapi function attempts to allocate memory for processing email attachment data, it fails to properly validate or handle cases where memory allocation requests cannot be fulfilled. This condition creates a scenario where an attacker can craft a specially designed TNEF file that, when processed by the vulnerable ytnef library, triggers an unhandled memory allocation failure. The flaw directly maps to CWE-691, which categorizes insufficient control flow management, and more specifically aligns with CWE-401, concerning memory leaks and resource leaks in software implementations.
The operational impact of this vulnerability extends beyond simple service disruption as it can be leveraged in various attack scenarios targeting systems that process email attachments or handle TNEF formatted data. Systems utilizing ytnef for email processing, document management, or collaboration platforms become vulnerable to denial of service attacks where attackers can consume system resources or cause application crashes through carefully constructed malicious files. The vulnerability particularly affects environments where automated email processing, spam filtering, or document ingestion systems rely on this library, potentially leading to cascading failures in email services, collaboration platforms, or enterprise document management systems.
Mitigation strategies for CVE-2017-12144 should prioritize immediate remediation through version updates to ytnef library versions that address the memory allocation handling issue. Organizations should implement input validation measures that filter or sanitize TNEF files before processing, particularly in environments where untrusted email attachments are handled. The implementation of resource limits and timeout mechanisms can help prevent attackers from exhausting system resources through prolonged exploitation attempts. Additionally, system administrators should monitor for unusual resource consumption patterns and implement intrusion detection systems that can identify potential exploitation attempts targeting this specific vulnerability. From an ATT&CK framework perspective, this vulnerability aligns with T1499.004, which covers network denial of service, and represents a classic example of resource exhaustion attacks that can be used to disrupt legitimate service availability.