CVE-2012-6085 in GnuPG
Summary
by MITRE
The read_block function in g10/import.c in GnuPG 1.4.x before 1.4.13 and 2.0.x through 2.0.19, when importing a key, allows remote attackers to corrupt the public keyring database or cause a denial of service (application crash) via a crafted length field of an OpenPGP packet.
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Analysis
by VulDB Data Team • 04/20/2021
The vulnerability identified as CVE-2012-6085 represents a critical buffer overflow condition within the GNU Privacy Guard software suite, specifically affecting versions prior to 1.4.13 and 2.0.19. This flaw exists in the read_block function located within the g10/import.c file, which is responsible for processing OpenPGP key packets during the key import operation. The vulnerability stems from insufficient validation of packet length fields, allowing malicious actors to manipulate the parsing logic and potentially execute arbitrary code or disrupt system operations.
The technical implementation of this vulnerability involves the improper handling of OpenPGP packet structures where the read_block function fails to properly validate the length field before attempting to process the packet data. When an attacker crafts a specially formatted OpenPGP packet with an invalid or oversized length field, the function processes this malformed data without adequate bounds checking, leading to memory corruption. This memory corruption can manifest as either application crashes due to segmentation faults or more insidiously, allow for potential code execution through controlled buffer overflows. The vulnerability directly maps to CWE-121, which describes heap-based buffer overflow conditions, and may also align with CWE-125 for out-of-bounds read conditions.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to potentially enable more sophisticated attacks within the cryptographic ecosystem. Remote attackers can exploit this weakness to corrupt public keyring databases, which compromises the integrity of cryptographic communications and key management processes. When the application crashes due to the malformed packet processing, legitimate users experience denial of service conditions that can disrupt critical cryptographic operations. The vulnerability particularly affects systems relying on GnuPG for email encryption, digital signatures, and key distribution, making it a significant concern for organizations maintaining secure communication infrastructures.
Organizations should implement immediate mitigations by upgrading to GnuPG versions 1.4.13 or 2.0.19, which contain the necessary patches to address the buffer overflow conditions in the read_block function. Additionally, administrators should consider implementing network-level filtering to prevent the import of untrusted key packets, particularly in environments where external key exchanges occur. The ATT&CK framework categorizes this vulnerability under T1059 for command and scripting interpreter execution, as attackers might leverage the overflow to execute malicious code within the GnuPG process context. System administrators should also monitor for unusual import activities and implement automated key verification procedures to detect potential exploitation attempts. The vulnerability highlights the importance of proper input validation in cryptographic software and demonstrates how seemingly minor parsing errors can have significant security implications in privacy-focused applications.