CVE-2017-11696 in Network Security Services
Summary
by MITRE
Heap-based buffer overflow in the __hash_open function in lib/dbm/src/hash.c in Mozilla Network Security Services (NSS) allows context-dependent attackers to have unspecified impact using a crafted cert8.db file.
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Analysis
by VulDB Data Team • 03/07/2025
The vulnerability identified as CVE-2017-11696 represents a critical heap-based buffer overflow within the Network Security Services (NSS) library, specifically within the __hash_open function located in lib/dbm/src/hash.c. This flaw exists in the hash database management component of NSS, which is a foundational security library used by various Mozilla products including Firefox, Thunderbird, and SeaMonkey. The vulnerability arises when processing maliciously crafted cert8.db files, which are database files used by NSS to store certificate and key information. The buffer overflow occurs during the parsing of these database files, where insufficient bounds checking allows an attacker to write beyond the allocated heap memory boundaries.
The technical nature of this vulnerability aligns with CWE-121, heap-based buffer overflow, which occurs when a program writes data beyond the boundaries of a heap-allocated buffer. The flaw is particularly concerning because it exists within a core security component that handles certificate management and cryptographic operations. Attackers can exploit this vulnerability by preparing a specially crafted cert8.db file that, when processed by NSS, triggers the buffer overflow condition. The unspecified impact mentioned in the CVE description indicates that the consequences could range from arbitrary code execution to denial of service, depending on the specific memory corruption patterns and exploitation techniques employed. This vulnerability operates in a context-dependent manner, meaning that successful exploitation requires the target system to process the malicious database file through NSS functions.
The operational impact of CVE-2017-11696 extends beyond simple exploitation scenarios, as it affects the fundamental security infrastructure of applications relying on NSS. Systems using affected versions of NSS could be compromised through various attack vectors including web browsing, email processing, or any application that handles certificate validation. The vulnerability demonstrates the critical importance of proper input validation and memory management in security libraries, as a flaw in the database parsing component can potentially lead to complete system compromise. From an attack perspective, this vulnerability maps to several ATT&CK techniques including T1059 for command execution and T1068 for exploit development, as attackers could leverage this to execute arbitrary code on vulnerable systems. The exploitation of this vulnerability could result in privilege escalation, data theft, or complete system takeover depending on the execution environment and target system configuration.
Mitigation strategies for CVE-2017-11696 should prioritize immediate patching of affected NSS versions, with organizations monitoring for updates from Mozilla and their respective software vendors. The recommended approach includes deploying NSS version 3.26 or later, which contains the necessary fixes for this buffer overflow vulnerability. Additionally, system administrators should implement strict file access controls on cert8.db files and other NSS database files to prevent unauthorized modification. Network segmentation and monitoring for suspicious database file access patterns can provide early detection of potential exploitation attempts. Security professionals should also consider implementing application whitelisting policies that restrict execution of NSS components from untrusted sources. The vulnerability highlights the necessity of regular security audits and vulnerability assessments of core security libraries, particularly those handling cryptographic operations and certificate management. Organizations should maintain updated threat intelligence feeds to monitor for related exploits and ensure comprehensive security posture through layered defensive measures including intrusion detection systems and endpoint protection solutions.