CVE-2017-5835 in libplist
Summary
by MITRE
libplist allows attackers to cause a denial of service (large memory allocation and crash) via vectors involving an offset size of zero.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 09/04/2020
The vulnerability identified as CVE-2017-5835 resides within the libplist library, a critical component in the processing of property list files across various operating systems including iOS, macOS, and Linux platforms. This library serves as a foundational element for parsing and generating plist files that are extensively used in system configuration, application settings, and device communication protocols. The flaw manifests when the library encounters a malformed property list structure where an offset size is set to zero, creating a dangerous condition that can be exploited by malicious actors to disrupt system operations. This vulnerability represents a classic case of improper input validation where the library fails to adequately sanitize the offset parameters during the parsing process, leading to unpredictable behavior that can be systematically manipulated.
The technical exploitation of this vulnerability occurs through the manipulation of property list file structures where an attacker crafts a malicious plist with an offset size of zero, which causes the libplist parser to attempt an excessive memory allocation operation. When the parser encounters this malformed input, it fails to properly validate the offset parameter, resulting in a memory allocation request that exceeds normal operational limits. This flaw can be categorized under CWE-129, which describes improper validation of array indices, and more specifically aligns with CWE-787, which covers out-of-bounds write operations. The vulnerability exists in the parsing logic where the library assumes valid offset values without proper bounds checking, creating a pathway for attackers to trigger memory allocation failures that ultimately lead to application crashes.
The operational impact of CVE-2017-5835 extends beyond simple denial of service conditions, as it can be leveraged in more sophisticated attack vectors that target system stability and availability. When exploited successfully, the vulnerability causes the affected applications to consume excessive memory resources and subsequently crash, potentially creating a denial of service scenario that affects legitimate users and system operations. The vulnerability is particularly concerning in environments where libplist is used for device communication protocols, as it can be exploited through device management systems, mobile device management solutions, or any application that processes user-provided property list data. This vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks, and can be used as part of broader attack chains targeting system availability and integrity.
Mitigation strategies for this vulnerability require immediate patching of affected systems and applications that rely on libplist for property list processing. System administrators should prioritize updating the libplist library to versions that include proper input validation and bounds checking for offset parameters. Additionally, implementing input sanitization measures at the application level can provide defense-in-depth protection against malformed property list data. Organizations should also consider deploying network monitoring solutions to detect unusual memory allocation patterns that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of robust input validation and proper resource management in security-critical libraries, as highlighted in the NIST SP 800-160 standard for secure software development practices. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in other libraries and applications that might be susceptible to similar memory allocation vulnerabilities.