CVE-2017-6439 in libplist
Summary
by MITRE
Heap-based buffer overflow in the parse_string_node function in bplist.c in libimobiledevice libplist 1.12 allows local users to cause a denial of service (out-of-bounds write) via a crafted plist file.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 09/09/2020
The heap-based buffer overflow vulnerability identified as CVE-2017-6439 resides within the libimobiledevice libplist library version 1.12, specifically within the parse_string_node function located in the bplist.c file. This vulnerability represents a critical security flaw that affects the processing of property list files, which are commonly used in iOS and macOS systems for configuration data and device communication protocols. The issue manifests when the library encounters a malformed or crafted plist file that triggers improper memory handling during string node parsing operations.
The technical flaw stems from inadequate input validation and memory boundary checking within the parse_string_node function. When processing a specially crafted plist file, the function fails to properly validate the size of string data before attempting to write to heap-allocated memory regions. This allows an attacker to manipulate the parsing logic and write data beyond the allocated buffer boundaries, resulting in an out-of-bounds write condition. The vulnerability is classified as a heap-based buffer overflow, which means the overflow occurs in heap memory rather than stack memory, making it particularly challenging to detect and exploit consistently.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it can potentially be leveraged for more sophisticated attacks. Local users who can influence the processing of plist files through legitimate means or by tricking applications into parsing malicious files can trigger the buffer overflow. This could lead to system instability, application crashes, and potentially arbitrary code execution depending on the specific memory corruption patterns. The vulnerability affects systems that utilize libimobiledevice for iOS device communication, including various development tools, backup utilities, and device management applications that rely on proper plist parsing functionality.
Mitigation strategies for CVE-2017-6439 should focus on immediate library updates and input validation improvements. System administrators and developers should upgrade to libplist versions that contain patches addressing this specific buffer overflow condition, typically those released after the vulnerability disclosure. Additionally, implementing strict input validation mechanisms, sanitizing all plist file inputs, and employing memory protection techniques such as stack canaries and address space layout randomization can help reduce the exploitability of similar vulnerabilities. This vulnerability aligns with CWE-121, heap-based buffer overflow, and may map to ATT&CK technique T1059 for execution through malicious file processing, emphasizing the importance of proper input sanitization and memory management practices in security-critical applications.
The vulnerability demonstrates the critical importance of proper memory management in security libraries that handle user-supplied data. Property list files are fundamental to iOS ecosystem communication and device management, making this vulnerability particularly concerning for developers working with mobile device interfaces. Organizations should conduct thorough vulnerability assessments of their systems that utilize libimobiledevice components and ensure comprehensive testing of input handling procedures to prevent similar buffer overflow conditions from compromising system integrity.