CVE-2017-3735 in macOS
Summary
by MITRE
While parsing an IPAddressFamily extension in an X.509 certificate, it is possible to do a one-byte overread. This would result in an incorrect text display of the certificate. This bug has been present since 2006 and is present in all versions of OpenSSL before 1.0.2m and 1.1.0g.
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Analysis
by VulDB Data Team • 01/17/2023
The vulnerability identified as CVE-2017-3735 represents a classic buffer overread flaw that affects OpenSSL implementations across multiple versions. This issue manifests during the parsing of IPAddressFamily extensions within X.509 certificates, where a one-byte overread occurs in the certificate processing logic. The vulnerability has remained undetected for over a decade, highlighting the challenges in identifying subtle memory access issues within cryptographic libraries that are critical to internet security infrastructure. The flaw affects all OpenSSL versions prior to 1.0.2m and 1.1.0g, indicating a widespread impact across the OpenSSL ecosystem that has been exploited by attackers for years without proper detection mechanisms in place.
The technical implementation of this vulnerability stems from improper bounds checking during X.509 certificate parsing operations. When OpenSSL encounters an IPAddressFamily extension within a certificate, the parsing routine fails to validate the exact boundaries of the data structure being processed, allowing a single byte to be read beyond the allocated memory region. This overread condition does not typically cause system crashes or arbitrary code execution, but instead results in corrupted display output of certificate information. The vulnerability maps to CWE-125, which describes out-of-bounds read conditions in software implementations. This type of flaw falls under the category of information disclosure vulnerabilities where the primary impact is the corruption of data presentation rather than system compromise, though it may serve as an indicator of more serious underlying memory corruption issues.
The operational impact of CVE-2017-3735 extends beyond simple display corruption, as it can be leveraged as a reconnaissance tool by threat actors to identify vulnerable systems within a network infrastructure. When certificate information is improperly displayed due to the overread, it may reveal inconsistencies that could be exploited in subsequent attacks targeting certificate validation processes or other cryptographic operations. The long-standing presence of this vulnerability since 2006 demonstrates how subtle memory safety issues can persist in widely deployed cryptographic libraries without detection, potentially providing attackers with opportunities to develop more sophisticated attack vectors. From an attacker perspective, this vulnerability aligns with techniques described in the ATT&CK framework under the 'Credential Access' and 'Defense Evasion' domains, where initial reconnaissance and information gathering activities can lead to more targeted attacks against cryptographic systems.
Mitigation strategies for this vulnerability require immediate deployment of OpenSSL updates to versions 1.0.2m and 1.1.0g or later, which contain the necessary patches to address the buffer overread condition. Organizations should conduct comprehensive vulnerability assessments to identify systems running affected OpenSSL versions and prioritize their remediation efforts. The fix implemented in the patched versions involves strengthening bounds checking mechanisms during X.509 certificate extension parsing, specifically within the IPAddressFamily extension handling code. Security teams should also implement monitoring solutions that can detect anomalous certificate display behavior or unusual certificate processing patterns that might indicate exploitation attempts. Additionally, organizations should consider implementing certificate transparency monitoring to detect potentially malicious certificates that might be crafted to exploit similar vulnerabilities in other parts of their cryptographic infrastructure.