CVE-2018-12913 in Miniz
Summary
by MITRE
In Miniz 2.0.7, tinfl_decompress in miniz_tinfl.c has an infinite loop because sym2 and counter can both remain equal to zero.
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Analysis
by VulDB Data Team • 03/29/2023
The vulnerability identified as CVE-2018-12913 represents a critical flaw in the Miniz compression library version 2.0.7 where the decompression function tinfl_decompress contains a logic error that can lead to an infinite loop condition. This issue specifically occurs within the miniz_tinfl.c source file during the decompression process, making it a significant concern for any application that relies on this library for handling compressed data. The flaw stems from the interaction between two variables sym2 and counter which can both maintain a value of zero throughout the decompression loop, causing the function to never progress toward completion. This type of vulnerability falls under the category of denial of service attacks as it can cause applications to hang indefinitely when processing malformed compressed data, effectively rendering the software unusable until manually terminated.
The technical root cause of this vulnerability lies in the improper handling of state variables within the decompression algorithm's control flow. When sym2 and counter both equal zero, the loop condition fails to advance the decompression process, creating a scenario where the function remains trapped in an infinite iteration cycle. This represents a classic example of a loop termination condition failure that violates fundamental programming principles and can be classified as a CWE-835 vulnerability according to the Common Weakness Enumeration catalog. The flaw demonstrates poor error handling and boundary condition management within the decompression logic, where the algorithm does not properly validate or handle edge cases that could occur during the decompression of compressed data streams.
The operational impact of this vulnerability extends beyond simple denial of service scenarios as it can affect any software system that utilizes the Miniz library for decompressing data. Applications that process user-uploaded files, network data streams, or any external compressed content become vulnerable to this attack vector, potentially allowing malicious actors to cause system resource exhaustion through sustained infinite loop conditions. This vulnerability can be particularly dangerous in server environments where multiple concurrent requests could be simultaneously affected, leading to widespread service disruption. The issue aligns with ATT&CK technique T1499.004 which covers network denial of service attacks, as the infinite loop can consume system resources and prevent legitimate operations from completing. Additionally, this vulnerability could be exploited as part of a broader attack chain where an attacker first gains access to a system and then uses this flaw to maintain persistence through resource exhaustion attacks.
Mitigation strategies for CVE-2018-12913 should prioritize immediate patching of the Miniz library to version 2.0.8 or later where this specific infinite loop condition has been addressed through proper variable handling and loop termination logic. Organizations should implement comprehensive input validation and sanitization measures when processing compressed data, including setting timeouts on decompression operations to prevent indefinite hanging. Network segmentation and access controls should be reinforced to limit exposure to potentially malicious compressed data inputs. The vulnerability also highlights the importance of regular security auditing and code review processes, particularly for cryptographic and compression libraries that handle untrusted data. System monitoring should include detection of abnormal resource consumption patterns that could indicate the occurrence of infinite loop conditions, and incident response procedures should be established to quickly address any exploitation attempts. Furthermore, developers should consider implementing defensive programming practices such as maximum iteration limits and proper state variable validation to prevent similar issues in custom implementations of compression algorithms.