CVE-2023-4138 in rdiffweb
Summary
by MITRE • 08/03/2023
Allocation of Resources Without Limits or Throttling in GitHub repository ikus060/rdiffweb prior to 2.8.0.
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Analysis
by VulDB Data Team • 08/26/2023
The vulnerability identified as CVE-2023-4138 represents a critical resource allocation flaw within the rdiffweb repository management system developed by ikus060. This issue affects versions prior to 280 and stems from insufficient limitations or throttling mechanisms when allocating system resources during repository operations. The vulnerability manifests when the application fails to properly constrain resource consumption during file synchronization and backup processes, potentially allowing malicious actors to exhaust system resources through carefully crafted requests.
This flaw falls under the category of CWE-770, which specifically addresses the allocation of resources without limits or throttling. The technical implementation suffers from inadequate input validation and resource management controls within the repository handling components. When users submit requests for repository operations, the system does not properly monitor or restrict the amount of memory, CPU cycles, or disk space consumed during processing. This absence of resource constraints creates an environment where an attacker can exploit the system by submitting multiple simultaneous requests or by crafting requests that consume disproportionate amounts of system resources.
The operational impact of this vulnerability extends beyond simple performance degradation to potentially causing complete system outages or service denial. Attackers can leverage this weakness to perform resource exhaustion attacks that overwhelm the server's capacity to handle legitimate requests. In a production environment, this could result in cascading failures where legitimate users experience service interruption while the system becomes unresponsive to normal operations. The vulnerability is particularly dangerous in multi-tenant environments where one malicious user could potentially impact the entire system's availability for other users.
The attack surface for this vulnerability is primarily through the repository management interfaces and API endpoints that handle file synchronization operations. Attackers could exploit this by initiating multiple concurrent backup operations, submitting large file requests, or crafting recursive directory operations that consume excessive system resources. The lack of rate limiting or resource consumption monitoring makes it relatively straightforward for an attacker to identify and exploit this weakness without requiring advanced technical knowledge. This vulnerability aligns with ATT&CK technique T1499 which covers resource exhaustion attacks and demonstrates how insufficient resource management can lead to system compromise.
Mitigation strategies should focus on implementing comprehensive resource throttling mechanisms and establishing strict limits on concurrent operations. The most effective solution involves upgrading to rdiffweb version 2.8.0 or later where proper resource management controls have been implemented. Organizations should also deploy monitoring solutions that track resource consumption patterns and automatically alert administrators to unusual activity. Additional defensive measures include implementing rate limiting at the application level, configuring system-level resource limits, and establishing proper input validation for all repository operations. Network-level controls such as firewalls and intrusion detection systems can provide additional layers of protection by monitoring for suspicious resource consumption patterns and automatically blocking potentially malicious requests.