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CVE-2025-53633: CWE-405: Asymmetric Resource Consumption (Amplification) in ctfer-io chall-manager

High
VulnerabilityCVE-2025-53633cvecve-2025-53633cwe-405
Published: Thu Jul 10 2025 (07/10/2025, 19:38:19 UTC)
Source: CVE Database V5
Vendor/Project: ctfer-io
Product: chall-manager

Description

Chall-Manager is a platform-agnostic system able to start Challenges on Demand of a player. When decoding a scenario (i.e. a zip archive), the size of the decoded content is not checked, potentially leading to zip bombs decompression. Exploitation does not require authentication nor authorization, so anyone can exploit it. It should nonetheless not be exploitable as it is highly recommended to bury Chall-Manager deep within the infrastructure due to its large capabilities, so no users could reach the system. Patch has been implemented by commit 14042aa and shipped in v0.1.4.

AI-Powered Analysis

AILast updated: 07/10/2025, 20:01:18 UTC

Technical Analysis

CVE-2025-53633 is a high-severity vulnerability affecting the ctfer-io chall-manager platform, a system designed to start Challenges on Demand for players in a platform-agnostic manner. The vulnerability arises from improper handling of zip archive decompression during scenario decoding. Specifically, the system does not verify the size of the decompressed content, which allows an attacker to craft a malicious zip archive (commonly known as a zip bomb) that expands to consume excessive system resources. This leads to asymmetric resource consumption or amplification, potentially causing denial of service (DoS) conditions by exhausting CPU, memory, or disk space. Notably, exploitation requires no authentication or authorization, meaning any remote attacker can trigger this vulnerability without user interaction or credentials. However, the vendor recommends deploying chall-manager deep within protected infrastructure layers to reduce exposure. The vulnerability affects all versions prior to 0.1.4, with a patch released in version 0.1.4 that mitigates the issue by implementing size checks on decompressed content. The CVSS 4.0 score is 8.7 (high), reflecting the network attack vector, no required privileges or user interaction, and a high impact on availability. There are no known exploits in the wild as of the publication date, but the ease of exploitation and potential impact make it a critical concern for organizations using this product.

Potential Impact

For European organizations using ctfer-io chall-manager, this vulnerability poses a significant risk to system availability and operational continuity. An attacker could remotely deploy a zip bomb to exhaust server resources, leading to service outages or degraded performance. This is particularly critical in environments where chall-manager is integrated into competitive or training platforms, such as cybersecurity competitions, educational institutions, or research labs. The lack of authentication requirements increases the attack surface, potentially allowing external threat actors to disrupt services without insider access. Additionally, if chall-manager is part of a larger infrastructure handling sensitive or time-critical challenges, the DoS could cascade, affecting dependent systems and users. European organizations with strict uptime requirements or regulatory obligations around service availability (e.g., financial institutions, critical infrastructure operators) may face compliance risks or reputational damage if impacted. Although the vendor recommends isolating chall-manager within secure network segments, misconfigurations or exposure to public networks could increase exploitation likelihood.

Mitigation Recommendations

1. Immediate upgrade to ctfer-io chall-manager version 0.1.4 or later, which includes the patch to validate decompressed content size and prevent zip bomb exploitation. 2. Network segmentation: Ensure chall-manager instances are deployed within isolated, internal network zones inaccessible from the public internet or untrusted networks. 3. Implement strict ingress filtering and firewall rules to restrict access to the chall-manager service only to trusted IP addresses or VPNs. 4. Monitor resource usage closely on servers running chall-manager for unusual spikes in CPU, memory, or disk utilization that may indicate exploitation attempts. 5. Employ application-layer controls such as file upload size limits and scanning of uploaded archives for malicious content before processing. 6. Conduct regular security audits and penetration tests focusing on chall-manager deployment to verify proper isolation and patch status. 7. Maintain up-to-date incident response plans to quickly identify and mitigate DoS attacks stemming from this vulnerability.

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Technical Details

Data Version
5.1
Assigner Short Name
GitHub_M
Date Reserved
2025-07-07T14:20:38.389Z
Cvss Version
4.0
State
PUBLISHED

Threat ID: 6870187fa83201eaaca986cd

Added to database: 7/10/2025, 7:46:07 PM

Last enriched: 7/10/2025, 8:01:18 PM

Last updated: 8/13/2025, 3:21:15 AM

Views: 14

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