CVE-2018-14739 in PBC
Summary
by MITRE
An issue was discovered in libpbc.a in cloudwu PBC through 2017-03-02. A SEGV can occur in pbc_pattern_set_default in pattern.c.
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Analysis
by VulDB Data Team • 04/27/2023
The vulnerability identified as CVE-2018-14739 represents a critical memory access issue within the libpbc.a library, specifically affecting the cloudwu PBC implementation through March 2, 2017. This flaw manifests as a segmentation fault during the execution of the pbc_pattern_set_default function located in the pattern.c source file. The issue arises from improper handling of memory operations that can lead to unauthorized memory access patterns and system instability. The library in question is commonly used for parsing and processing binary protocol buffers, making it a critical component in various network communication and data serialization applications. The vulnerability demonstrates a classic example of a buffer over-read condition that can be exploited to cause application crashes or potentially enable more sophisticated attack vectors.
The technical root cause of this vulnerability stems from inadequate input validation and memory management within the pattern.c file. When the pbc_pattern_set_default function processes certain input patterns, it fails to properly validate the boundaries of memory allocations, leading to a situation where the application attempts to access memory regions that have not been properly initialized or are outside the allocated memory space. This type of flaw falls under the CWE-125 vulnerability category, which specifically addresses out-of-bounds read conditions. The improper handling of default pattern settings creates a scenario where malformed input data can trigger unexpected memory access patterns that result in segmentation faults. The vulnerability is particularly concerning because it occurs during pattern initialization, which is a fundamental operation that typically executes early in the library's lifecycle, potentially affecting the entire application's stability.
The operational impact of CVE-2018-14739 extends beyond simple application crashes, as it can be leveraged to create denial of service conditions that affect system availability. When exploited, this vulnerability can cause applications using the affected library to terminate unexpectedly, potentially disrupting critical services or data processing workflows. The segmentation fault behavior makes this vulnerability particularly dangerous in production environments where system stability is paramount, as it can lead to cascading failures across dependent services. In networked applications, this flaw could be exploited by malicious actors to continuously crash services, effectively creating a denial of service attack vector. The vulnerability's impact is amplified when considering that PBC libraries are commonly integrated into various network protocols, data processing systems, and communication frameworks where reliability is essential. From an attacker's perspective, this vulnerability aligns with ATT&CK technique T1499.004, which involves network denial of service attacks, and T1059.007, which covers scripting through command-line interpreters, as exploitation may involve crafting specific input patterns to trigger the memory access violation.
Mitigation strategies for CVE-2018-14739 should focus on immediate library updates and code-level protections. Organizations using the affected libpbc.a library should prioritize upgrading to versions that contain proper memory boundary checks and input validation routines. The recommended approach includes implementing comprehensive input sanitization within the pattern.c file, ensuring that all memory access operations include proper boundary validation before any read or write operations occur. Additionally, developers should consider implementing defensive programming practices such as bounds checking, memory allocation validation, and proper error handling for pattern initialization routines. System administrators should monitor for any unusual segmentation fault occurrences in applications that utilize this library, as these events may indicate exploitation attempts. The vulnerability serves as a reminder of the importance of proper memory management in C/C++ based libraries and highlights the need for comprehensive testing of input validation mechanisms. Organizations should also consider implementing runtime protections such as address space layout randomization and stack canaries to mitigate potential exploitation scenarios, though the most effective solution remains the timely patching of the vulnerable library version.