CVE-2016-2180 in OpenSSL
Summary
by MITRE
The TS_OBJ_print_bio function in crypto/ts/ts_lib.c in the X.509 Public Key Infrastructure Time-Stamp Protocol (TSP) implementation in OpenSSL through 1.0.2h allows remote attackers to cause a denial of service (out-of-bounds read and application crash) via a crafted time-stamp file that is mishandled by the "openssl ts" command.
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Analysis
by VulDB Data Team • 08/29/2024
The vulnerability identified as CVE-2016-2180 resides within the OpenSSL cryptographic library's implementation of the X.509 Public Key Infrastructure Time-Stamp Protocol. This protocol enables the creation and verification of time-stamped digital signatures, which are critical for establishing cryptographic timestamps on documents and data. The flaw specifically affects OpenSSL versions through 1.0.2h and manifests in the TS_OBJ_print_bio function located in the crypto/ts/ts_lib.c file. This function is responsible for printing time-stamp objects in a human-readable format, a capability frequently utilized when processing time-stamp responses through the openssl ts command interface.
The technical nature of this vulnerability stems from inadequate input validation within the TS_OBJ_print_bio function. When a maliciously crafted time-stamp file is processed by the openssl ts command, the function fails to properly validate the structure and content of the timestamp data before attempting to read from it. This improper handling results in an out-of-bounds memory read operation, where the program attempts to access memory locations beyond the allocated buffer boundaries. The vulnerability is classified as a buffer over-read condition, which can be categorized under CWE-125 as "Out-of-bounds Read" and represents a classic example of improper input validation leading to memory safety issues.
The operational impact of this vulnerability extends beyond simple denial of service, as it provides attackers with a mechanism to crash applications that utilize OpenSSL's time-stamp processing capabilities. The out-of-bounds read can cause unpredictable behavior including application crashes, memory corruption, or potentially more severe consequences depending on the execution environment. In practical scenarios, this vulnerability affects any system that processes time-stamp responses from trusted timestamp authorities, particularly systems implementing certificate validation workflows or time-stamping services. The vulnerability is particularly concerning in environments where automated timestamp verification processes are employed, as it could be exploited to disrupt critical security infrastructure operations.
Security practitioners should consider this vulnerability in the context of the MITRE ATT&CK framework, specifically under the T1499.004 technique related to "Endpoint Denial of Service" and potentially T1595.001 for "Phishing for Information" if attackers attempt to leverage this weakness to disrupt services. The vulnerability demonstrates how seemingly benign cryptographic protocols can contain critical security flaws that affect the broader security ecosystem. Organizations should prioritize updating their OpenSSL installations to versions beyond 1.0.2h, as this represents the first patch release addressing the issue. Additionally, system administrators should implement monitoring for unusual application crashes or memory access patterns when processing time-stamp data, as these could indicate exploitation attempts. The vulnerability also underscores the importance of thorough input validation in cryptographic libraries and highlights the need for comprehensive security testing of protocol implementations to prevent similar issues in future releases.