CVE-2017-5335 in GnuTLS
Summary
by MITRE
The stream reading functions in lib/opencdk/read-packet.c in GnuTLS before 3.3.26 and 3.5.x before 3.5.8 allow remote attackers to cause a denial of service (out-of-memory error and crash) via a crafted OpenPGP certificate.
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Analysis
by VulDB Data Team • 10/28/2022
The vulnerability identified as CVE-2017-5335 represents a critical denial of service flaw affecting GnuTLS versions prior to 3.3.26 and 3.5.8. This issue resides within the stream reading functions of the OpenCDK library component, specifically in the file lib/opencdk/read-packet.c. The flaw manifests when processing crafted OpenPGP certificates, enabling remote attackers to trigger system instability through memory exhaustion attacks. The vulnerability demonstrates particular concern for systems relying on GnuTLS for secure communications and OpenPGP certificate handling, as it can be exploited without requiring authentication or specialized privileges.
The technical implementation of this vulnerability stems from inadequate input validation and memory management within the packet reading logic of OpenCDK. When GnuTLS processes OpenPGP certificates, the stream reading functions fail to properly validate packet sizes and structure constraints, allowing maliciously crafted certificates to specify excessively large memory allocations. This leads to out-of-memory conditions that cause the application to crash or become unresponsive. The flaw operates at the protocol parsing layer, where the system attempts to allocate memory based on malformed packet headers without proper bounds checking, creating a classic buffer overflow scenario that manifests as memory exhaustion rather than traditional code execution.
The operational impact of CVE-2017-5335 extends beyond simple service disruption, as it can affect any system utilizing GnuTLS for OpenPGP certificate processing. Attackers can leverage this vulnerability to perform distributed denial of service attacks against services that depend on GnuTLS, particularly web servers, email systems, and secure communication platforms. The vulnerability affects not only direct applications but also systems that integrate GnuTLS as a dependency, amplifying the potential attack surface. Organizations running affected versions face significant risk of system unavailability and potential data loss during exploitation attempts, making this a critical concern for enterprise security operations.
Mitigation strategies for CVE-2017-5335 primarily focus on immediate version upgrades to GnuTLS 3.3.26 or 3.5.8, which contain the necessary patches to address the memory allocation validation issues. System administrators should prioritize patching affected systems and monitoring for exploitation attempts through network intrusion detection systems. Additional protective measures include implementing network segmentation to limit exposure, configuring resource limits on affected services to prevent complete system crashes, and establishing monitoring protocols for unusual memory consumption patterns. Organizations should also consider implementing input validation controls at network boundaries and conducting comprehensive vulnerability assessments to identify other potentially affected components within their infrastructure. This vulnerability aligns with CWE-129 and CWE-772 categories, representing improper input validation and insufficient resource management respectively, and maps to ATT&CK technique T1499 for network denial of service attacks.