CVE-2017-11367 in shoco
Summary
by MITRE
The shoco_decompress function in the API in shoco through 2017-07-17 allows remote attackers to cause a denial of service (buffer over-read and application crash) via malformed compressed data.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 12/13/2022
The shoco_decompress function vulnerability represents a critical buffer over-read flaw that affects the shoco compression library version 2017-07-17 and earlier. This vulnerability exists within the application programming interface of the shoco library, which is designed for efficient compression of short strings. The flaw manifests when the decompression function processes malformed compressed data, creating a scenario where the application attempts to read beyond the bounds of allocated memory buffers. This specific vulnerability demonstrates a classic buffer over-read condition that can be exploited by remote attackers to disrupt service availability.
The technical implementation of this vulnerability stems from inadequate input validation within the decompression algorithm. When shoco encounters compressed data that does not conform to expected format specifications, the decompression routine fails to properly bounds-check memory accesses during the decompression process. This allows maliciously crafted compressed data to cause the function to read memory locations beyond the intended buffer boundaries. The vulnerability is particularly concerning because it operates at the API level, meaning any application or service that relies on shoco for decompression is potentially exposed to this attack vector without requiring elevated privileges or complex exploitation techniques.
The operational impact of CVE-2017-11367 extends beyond simple application crashes to encompass broader service disruption scenarios. Remote attackers can leverage this vulnerability to execute denial of service attacks against systems that utilize shoco for data compression and decompression. The vulnerability affects any system where compressed data might be processed, including web applications, network services, and embedded systems that employ shoco for efficient data handling. The crash occurs during decompression operations, making it particularly dangerous for services that continuously process external data streams or user-provided content that may contain compressed data. This vulnerability can be exploited in scenarios such as web servers processing compressed request data, network protocols handling compressed payloads, or any system that accepts and decompresses data from untrusted sources.
Mitigation strategies for this vulnerability focus on immediate library updates and input validation improvements. The primary recommendation involves upgrading to shoco versions released after July 17, 2017, which contain the necessary patches to address the buffer over-read condition. Organizations should implement comprehensive input validation mechanisms that verify compressed data integrity before processing, utilizing techniques such as checksum validation or format verification. Additionally, implementing proper error handling and memory access bounds checking within applications that utilize shoco can provide defense-in-depth protection. The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and can be mapped to ATT&CK technique T1499.004 for network denial of service attacks. System administrators should also consider implementing network segmentation and monitoring for suspicious decompression activities that might indicate exploitation attempts.