Kerio Control: Improper Neutralization of CRLF Sequences in HTTP Headers
CVE-2024-52875 is a high-severity improper neutralization of CRLF sequences in HTTP headers vulnerability in Kerio Control from Gfi, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. Affected Kerio Control versions: 9.2.5 through 9.4.5. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 29.4% chance of exploitation within 30 days, which is in the top 1.79% of all scored CVEs.
EPSS places it among the vulnerabilities most likely to be exploited soon.
What to do
- Check which version of Kerio Control you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| GFI | Kerio Control | 9.2.5 through 9.4.5 | 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
- RequiredA user must take an action such as opening a file or link.
- 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:R/S:U/C:H/I:H/A:H. Scored by CNA (mitre.org).
Official description
An issue was discovered in GFI Kerio Control 9.2.5 through 9.4.5. The dest GET parameter passed to the /nonauth/addCertException.cs and /nonauth/guestConfirm.cs and /nonauth/expiration.cs pages is not properly sanitized before being used to generate a Location HTTP header in a 302 HTTP response. This can be exploited to perform Open Redirect or HTTP Response Splitting attacks, which in turn lead to Reflected Cross-Site Scripting (XSS). Remote command execution can be achieved by leveraging the upgrade feature in the admin interface.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of CRLF Sequences in HTTP Headers
The product receives data from an HTTP agent/component (e.g., web server, proxy, browser, etc.), but it does not neutralize or incorrectly neutralizes CR and LF characters before the data is included in outgoing HTTP headers.
How developers prevent this class of flaw
- Construct HTTP headers very carefully, avoiding the use of non-validated input data.
- Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.
More Improper Neutralization of CRLF Sequences in HTTP Headers vulnerabilities (CWE-113)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Technical write-ups (may include proof of concept)
- karmainsecurity.com/hacking-kerio-control-via-cve-2024-52875Exploit, Third Party Advisory
- seclists.org/fulldisclosure/2024/Dec/15Exploit, Mailing List, Third Party Advisory
Recent Improper Neutralization of CRLF Sequences in HTTP Headers vulnerabilities
- 7.5 High severity
Spotted an error? Tell us.