CVE-2015-7987 in mDNSResponder
Summary
by MITRE
Multiple buffer overflows in mDNSResponder before 625.41.2 allow remote attackers to read or write to out-of-bounds memory locations via vectors involving the (1) GetValueForIPv4Addr, (2) GetValueForMACAddr, (3) rfc3110_import, or (4) CopyNSEC3ResourceRecord function.
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Analysis
by VulDB Data Team • 11/11/2024
The vulnerability identified as CVE-2015-7987 represents a critical security flaw in Apple's mDNSResponder service, which is integral to macOS and iOS operating systems for implementing multicast dns functionality. This vulnerability affects mDNSResponder versions prior to 625.41.2 and manifests through multiple buffer overflow conditions that can be exploited remotely by attackers to gain unauthorized access to memory locations beyond the bounds of allocated buffers. The flaw specifically impacts four distinct functions within the service including GetValueForIPv4Addr, GetValueForMACAddr, rfc3110_import, and CopyNSEC3ResourceRecord, each representing different attack vectors that leverage improper memory handling mechanisms.
The technical implementation of this vulnerability stems from inadequate bounds checking in the memory management routines of mDNSResponder. When processing network packets or data structures containing DNS records, these functions fail to validate the size of incoming data before copying it into fixed-size buffers. This lack of proper input validation creates opportunities for attackers to craft malicious payloads that exceed buffer boundaries, resulting in memory corruption that can be leveraged for arbitrary code execution or information disclosure. The vulnerability operates at the network layer where mDNSResponder processes incoming DNS queries and responses, making it particularly dangerous as it can be triggered through normal network operations without requiring user interaction or authentication.
The operational impact of CVE-2015-7987 extends beyond simple memory corruption, as it provides attackers with potential pathways for privilege escalation and system compromise. Remote attackers can exploit these buffer overflows to read sensitive information from memory locations or write malicious data to arbitrary memory addresses, potentially enabling them to execute code with the privileges of the mDNSResponder process. This could lead to complete system compromise, especially when combined with other exploitation techniques or when the affected service runs with elevated privileges. The vulnerability affects a core networking component that is active on virtually all Apple devices, making it a high-value target for attackers seeking persistent access to affected systems.
Security professionals should note that this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and demonstrates characteristics consistent with ATT&CK technique T1059.007 for command and scripting interpreter. The affected functions represent specific attack surfaces where network-based exploitation can occur, with the rfc3110_import function being particularly concerning as it handles DNSSEC key data processing. Organizations should prioritize patching affected systems to version 625.41.2 or later, as Apple released this update to address the memory handling issues in the mDNSResponder service. Network segmentation and monitoring of DNS traffic can provide additional defense-in-depth measures while waiting for patches, though these are not substitutes for proper remediation. The vulnerability underscores the importance of proper input validation and bounds checking in network services, particularly those handling untrusted data from external sources.