Rejetto HTTP File Server Improper Neutralization of Special Elements Used in a Template Engine
CVE-2024-23692 is a critical-severity improper control of generation of code vulnerability in HTTP File Server from Rejetto, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected HTTP File Server versions: 2.3m and earlier. The record does not name a fixed version, so check the vendor advisory. CISA added it to the Known Exploited Vulnerabilities catalogue on July 9, 2024, which means attacks have been observed in the wild, including in ransomware campaigns.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Check which version of HTTP File Server you run against the affected versions below, and install the vendor's latest release.
- CISA's required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Rejetto | HTTP File Server | 2.3m and earlier | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 9.8 | Critical | CNA (vulncheck.com) |
| CVSS 3.1 | 9.8 | Critical | NVD |
Official description
Rejetto HTTP File Server, up to and including version 2.3m, is vulnerable to a template injection vulnerability. This vulnerability allows a remote, unauthenticated attacker to execute arbitrary commands on the affected system by sending a specially crafted HTTP request. As of the CVE assignment date, Rejetto HFS 2.3m is no longer supported.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: 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.
How developers prevent this class of flaw
- Refactor your program so that you do not have to dynamically generate code.
- Run your code in a jail or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which code can be executed by your product. Examples include the Unix chroot jail and AppArmor. In general, managed code may provide some protection. This may not be a feasible solution, and it only limits the impact to the operating system; the rest of your application may still be subject to compromise. Be careful to avoid CWE-243 and other weaknesses related to jails.
- Use dynamic tools and techniques that interact with the product using large test suites with many diverse inputs, such as fuzz testing (fuzzing), robustness testing, and fault injection. The product's operation may slow down, but it should not become unstable, crash, or generate incorrect results.
More Improper Control of Generation of Code vulnerabilities (CWE-94)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: active, automatable: yes, technical impact: total).
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Deadline for US federal agencies to remediate, set by CISA.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- github.com/rapid7/metasploit-framework/pull/19240Exploit, Issue Tracking
Third-party and government advisories
- vulncheck.com/advisories/rejetto-unauth-rceThird Party Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-23692US Government Resource
Technical write-ups (may include proof of concept)
- mohemiv.com/all/rejetto-http-file-server-2-3m-unauthenticated-rce/Exploit
- vicarius.io/vsociety/posts/cve-2024-23692-detect-rejetto-hfs-vulnerabilityExploit, Third Party Advisory
- vicarius.io/vsociety/posts/cve-2024-23692-rejetto-hfs-mitigate-vulnerabilityExploit, Third Party Advisory
- vicarius.io/vsociety/posts/unauthenticated-rce-flaw-in-rejetto-http-file-server-cve-2024-23692Exploit, Third Party Advisory
Other vulnerabilities in HTTP File Server
- 8.8 High severity
- 7.5 High severity
- 9.8 Critical severity
Recent Improper Control of Generation of Code vulnerabilities
- 7.8 High severity
- 8.1 High severity
- 8.8 High severity
- 7.3 High severity
- 9.8 Critical severity
- 8.4 High severity
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