CVE-2016-2105 in MySQL Server
Summary
by MITRE
Integer overflow in the EVP_EncodeUpdate function in crypto/evp/encode.c in OpenSSL before 1.0.1t and 1.0.2 before 1.0.2h allows remote attackers to cause a denial of service (heap memory corruption) via a large amount of binary data.
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Analysis
by VulDB Data Team • 09/08/2022
The vulnerability identified as CVE-2016-2105 represents a critical integer overflow flaw within OpenSSL's cryptographic library implementation. This issue affects the EVP_EncodeUpdate function located in the crypto/evp/encode.c file, which is part of the OpenSSL library used extensively across web servers, applications, and security infrastructure. The vulnerability specifically manifests in OpenSSL versions prior to 1.0.1t and 1.0.2h, creating a significant risk for systems relying on these older cryptographic implementations.
The technical nature of this flaw stems from improper handling of integer arithmetic during the encoding process. When the EVP_EncodeUpdate function processes large amounts of binary data, it fails to properly validate or constrain the integer values used in memory allocation calculations. This oversight creates a condition where an attacker can manipulate input data to cause integer overflow, resulting in incorrect memory allocation sizes that ultimately lead to heap memory corruption. The vulnerability operates through a classic integer overflow scenario where the calculation of required buffer space exceeds the maximum representable value for the integer type, causing the system to allocate insufficient memory or potentially trigger memory corruption patterns.
From an operational perspective, this vulnerability enables remote attackers to execute denial of service attacks against systems utilizing affected OpenSSL versions. The heap memory corruption resulting from the integer overflow can cause applications to crash, become unresponsive, or exhibit unpredictable behavior. The attack requires minimal privileges and can be executed remotely, making it particularly dangerous in web server environments where OpenSSL is commonly used for SSL/TLS encryption. Systems handling large volumes of binary data or those exposed to untrusted input streams face the highest risk of exploitation, as the vulnerability becomes more apparent when processing substantial data sets that trigger the overflow condition.
The impact of this vulnerability aligns with CWE-190, which categorizes integer overflow conditions as a fundamental weakness in software design. This classification reflects the core issue where integer arithmetic operations exceed their defined limits, creating exploitable conditions for memory corruption. From an adversarial perspective, this vulnerability maps to ATT&CK technique T1499.004, which covers network denial of service attacks, specifically targeting application availability through memory corruption techniques. The vulnerability's exploitation pathway demonstrates how seemingly benign cryptographic operations can become attack vectors when integer handling is inadequate. Organizations should prioritize immediate patching of affected systems, as the vulnerability provides attackers with a straightforward method to disrupt services without requiring specialized knowledge or privileged access. System administrators must also implement monitoring for unusual memory allocation patterns and consider network segmentation to limit the potential impact of exploitation attempts against critical infrastructure components relying on OpenSSL implementations.