CVE-2014-3564 in GnuPG Made Easy
Summary
by MITRE
Multiple heap-based buffer overflows in the status_handler function in (1) engine-gpgsm.c and (2) engine-uiserver.c in GPGME before 1.5.1 allow remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via vectors related to "different line lengths in a specific order."
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Analysis
by VulDB Data Team • 12/16/2024
The vulnerability identified as CVE-2014-3564 represents a critical heap-based buffer overflow issue affecting GPGME versions prior to 1.5.1. This flaw resides within the status_handler function in two distinct source files: engine-gpgsm.c and engine-uiserver.c. The vulnerability stems from improper handling of input data where the software fails to adequately validate or constrain buffer boundaries when processing status information from GPG operations. Attackers can exploit this weakness by crafting malicious input sequences that manipulate line lengths in a specific order, leading to memory corruption that manifests as heap corruption.
The technical exploitation of this vulnerability occurs through manipulation of the status handling mechanism within GPGME's engine components. When the status_handler function processes incoming data, it does not properly account for varying line lengths that could exceed allocated buffer boundaries. This particular flaw falls under the CWE-121 heap-based buffer overflow category, which represents a common class of memory safety vulnerabilities where data written to a buffer exceeds its allocated size. The specific conditions require attackers to send carefully crafted input that creates a sequence of operations where different line lengths are processed in a particular order, triggering the buffer overflow condition. The vulnerability demonstrates characteristics consistent with CWE-787, which describes out-of-bounds writes that can occur when an application writes data past the end of a buffer.
Operationally, this vulnerability presents significant risk to systems utilizing GPGME for cryptographic operations, particularly in environments where untrusted data sources may interact with the software. The impact encompasses both denial of service and potential remote code execution capabilities, making it particularly dangerous for applications that process status information from external sources. When exploited, the vulnerability causes the targeted processes to crash, resulting in service disruption that can be leveraged for persistent denial of service attacks. The potential for arbitrary code execution further amplifies the risk, as attackers could potentially gain control over affected systems. This vulnerability affects systems using GPGME in various configurations including email clients, file encryption tools, and other applications that rely on GPG for security operations. The attack vector typically involves manipulation of status messages that GPGME receives during cryptographic operations, making it particularly relevant for applications that interface with GPG services through engine components.
Mitigation strategies for CVE-2014-3564 primarily focus on immediate version upgrades to GPGME 1.5.1 or later, which contain patches addressing the buffer overflow conditions. System administrators should prioritize updating all affected installations and verify that the updated versions properly address the specific buffer handling issues in both engine-gpgsm.c and engine-uiserver.c files. Additional defensive measures include implementing input validation controls and monitoring for anomalous status message patterns that could indicate exploitation attempts. Organizations should also consider network segmentation and access controls to limit exposure of systems that process untrusted GPG status information. The vulnerability's classification under ATT&CK technique T1203, which covers exploitation of software vulnerabilities, underscores the importance of maintaining current software versions and applying security patches promptly. Regular security assessments and vulnerability scanning should be conducted to identify any remaining instances of older GPGME versions that may still be in use within the environment.