CVE-2022-42964 in pymatgen
Summary
by MITRE • 11/09/2022
An exponential ReDoS (Regular Expression Denial of Service) can be triggered in the pymatgen PyPI package, when an attacker is able to supply arbitrary input to the GaussianInput.from_string method
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Analysis
by VulDB Data Team • 12/11/2022
The vulnerability CVE-2022-42964 represents a critical security flaw in the pymatgen Python package that exposes applications to exponential Regular Expression Denial of Service attacks. This vulnerability specifically affects the GaussianInput.from_string method which processes user-supplied input through regular expressions. When an attacker crafts malicious input strings that exploit poorly designed regular expressions, the system can experience dramatic performance degradation or complete service unavailability. The issue stems from the way the package handles regular expression patterns that can cause catastrophic backtracking during pattern matching operations, leading to exponential time complexity growth. This type of vulnerability falls under the CWE-400 category of Uncontrolled Resource Consumption and aligns with ATT&CK technique T1499.004 for Resource Exhaustion attacks.
The technical implementation of this vulnerability occurs within the pymatgen library's Gaussian input parsing functionality where regular expressions are used to parse and validate molecular structure data. The flawed regex patterns create opportunities for attackers to craft input strings that trigger backtracking behavior in the regular expression engine. When such input passes through the GaussianInput.from_string method, the regular expression engine must explore an exponentially growing number of possible matching paths, causing CPU utilization to spike and potentially leading to application hangs or crashes. The vulnerability is particularly dangerous because it can be exploited through user-controllable inputs, making it accessible to attackers who can supply arbitrary data to the application. This creates a significant risk for applications that rely on pymatgen for processing molecular data, especially in environments where external input is accepted without proper sanitization.
The operational impact of CVE-2022-42964 extends beyond simple performance degradation to encompass complete system availability risks. Applications using vulnerable versions of pymatgen become susceptible to denial of service conditions that can affect critical scientific computing workflows, data processing pipelines, and research applications. The exponential nature of the attack means that even relatively small malicious inputs can cause substantial resource consumption, potentially affecting multiple concurrent processes or entire application instances. This vulnerability is particularly concerning in cloud environments or shared computing resources where a single exploited service could impact broader system availability. The attack vector is easily accessible since it only requires supplying malformed input to the GaussianInput.from_string method, making it a low-effort, high-impact threat that can be exploited by attackers with minimal technical expertise.
Mitigation strategies for CVE-2022-42964 should focus on both immediate patching and defensive programming practices. The primary solution involves upgrading to a patched version of the pymatgen package where the vulnerable regular expression patterns have been replaced with more efficient alternatives that prevent catastrophic backtracking. Organizations should also implement input validation and sanitization measures that limit the complexity of regular expressions used in parsing operations. Additional defensive measures include implementing timeouts for regular expression operations, using regex engines that support timeout mechanisms, and conducting regular security assessments of third-party libraries. The ATT&CK framework suggests implementing process isolation and monitoring for unusual CPU consumption patterns as early detection mechanisms. Security teams should also consider implementing network-level protections and application firewalls to limit exposure to potentially malicious input, while maintaining comprehensive logging to track any exploitation attempts. Organizations using pymatgen in production environments should conduct thorough testing of patched versions to ensure compatibility and prevent regressions in their scientific computing workflows.