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CVE-2024-4040: CrushFTP VFS Sandbox Escape Vulnerability
CVE-2024-4040 is rated critical with a CVSS v3.1 base score of 10.0 and affects CrushFTP CrushFTP. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available. CISA added it to its Known Exploited Vulnerabilities catalog on 2024-04-24, which means exploitation in the wild has been observed.
Vulnerability description
A server side template injection vulnerability in CrushFTP in all versions before 10.7.1 and 11.1.0 on all platforms allows unauthenticated remote attackers to read files from the filesystem outside of the VFS Sandbox, bypass authentication to gain administrative access, and perform remote code execution on the server.
Severity breakdown
CVSS v3.1 10.0: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
- Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
- Attack complexity: Low. No special conditions; the attack can be repeated reliably.
- Privileges required: None. No account or prior access is needed.
- User interaction: None. No action from any user is needed.
- Scope: Changed. Impact reaches beyond the vulnerable component to other resources.
- Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
- Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
- Availability impact: High. Total loss of availability; the component can be shut down.
Underlying weakness
CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine
The product uses a template engine to insert or process externally-influenced input, but it does not neutralize or incorrectly neutralizes special elements or syntax that can be interpreted as template expressions or other code directives when processed by the engine.
CWE-94: Improper Control of Generation of Code
The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.
Affected products
- Crushftp: from 10.0.0 before 10.7.1; from 11.0.0 before 11.1.0
References
- https://www.crushftp.com/crush10wiki/Wiki.jsp?page=Update
- https://www.crushftp.com/crush11wiki/Wiki.jsp?page=Update
- https://www.reddit.com/r/cybersecurity/comments/1c850i2/all_versions_of_crush_ftp_are_vulnerable/
- https://github.com/airbus-cert/CVE-2024-4040
- https://www.bleepingcomputer.com/news/security/crushftp-warns-users-to-patch-exploited-zero-day-immediately/
- https://www.rapid7.com/blog/post/2024/04/23/etr-unauthenticated-crushftp-zero-day-enables-complete-server-compromise/
- https://www.reddit.com/r/crowdstrike/comments/1c88788/situational_awareness_20240419_crushftp_virtual/
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-4040