CVE-2015-1606 in GnuPG
Summary
by MITRE
The keyring DB in GnuPG before 2.1.2 does not properly handle invalid packets, which allows remote attackers to cause a denial of service (invalid read and use-after-free) via a crafted keyring file.
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Analysis
by VulDB Data Team • 11/24/2024
The vulnerability identified as CVE-2015-1606 affects GnuPG keyring database handling mechanisms in versions prior to 2.1.2, representing a critical security flaw that enables remote attackers to execute denial of service attacks through carefully crafted malicious keyring files. This vulnerability resides within the core packet processing logic of GnuPG's keyring management system, where insufficient validation of packet structures leads to exploitable conditions that can compromise system stability and availability. The flaw specifically manifests when the keyring database encounters invalid or malformed packets during processing, creating opportunities for attackers to manipulate the software's internal state through crafted input.
The technical implementation of this vulnerability involves improper error handling within GnuPG's keyring packet parsing routines, where the software fails to adequately validate packet boundaries and structure integrity before processing. When encountering malformed packets, the system attempts to access memory locations that have already been freed or read invalid memory regions, resulting in use-after-free conditions and invalid read operations. This behavior stems from inadequate bounds checking and memory management practices within the keyring database processing code, which does not properly sanitize or reject malformed input before attempting to parse and utilize the data. The vulnerability operates at the protocol level where GnuPG processes keyring files containing public keys, secret keys, and associated metadata, making it particularly dangerous as keyring files are commonly shared and imported across different systems.
The operational impact of CVE-2015-1606 extends beyond simple denial of service, as it represents a potential vector for more sophisticated attacks that could compromise system integrity and availability. Remote attackers can exploit this vulnerability by preparing malicious keyring files that contain specially crafted invalid packets designed to trigger the use-after-free conditions within GnuPG's processing pipeline. The consequences include system crashes, application instability, and potential privilege escalation scenarios depending on how the vulnerable system processes imported keyring files. This vulnerability directly relates to CWE-476 which addresses NULL pointer dereferences and related memory management issues, while also mapping to ATT&CK technique T1203 which involves legitimate program execution through manipulation of system resources. The attack surface is particularly broad given that GnuPG keyring files are frequently exchanged in secure communications, making this vulnerability particularly dangerous in environments where automated keyring imports or system-wide keyring management occurs.
Mitigation strategies for CVE-2015-1606 primarily focus on upgrading to GnuPG version 2.1.2 or later, which includes comprehensive fixes for the packet validation and memory management issues that enabled this vulnerability. System administrators should implement strict keyring file validation procedures, including verification of file integrity and source authenticity before importing keyring files into production environments. Network-level controls can be implemented to filter and monitor keyring file transfers, particularly in environments where automated keyring distribution occurs. Additionally, organizations should establish robust keyring management policies that limit the scope of trusted keyring sources and implement regular keyring auditing procedures. The vulnerability highlights the importance of proper input validation and memory management practices, which aligns with security frameworks such as the OWASP Top Ten and NIST cybersecurity guidelines that emphasize the need for robust error handling and resource management in cryptographic software implementations.