RestSharp up to 111.x RestRequest.AddHeader crlf injection

Summaryinfo

A vulnerability was found in RestSharp up to 111.x and classified as critical. This affects the function RestRequest.AddHeader. Executing a manipulation can lead to crlf injection. This vulnerability is handled as CVE-2024-45302. The attack can be executed remotely. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability has been found in RestSharp up to 111.x and classified as critical. This vulnerability affects the function RestRequest.AddHeader. The manipulation with an unknown input leads to a crlf injection vulnerability. The CWE definition for the vulnerability is CWE-93. The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

RestSharp is a Simple REST and HTTP API Client for .NET. The second argument to `RestRequest.AddHeader` (the header value) is vulnerable to CRLF injection. The same applies to `RestRequest.AddOrUpdateHeader` and `RestClient.AddDefaultHeader`. The way HTTP headers are added to a request is via the `HttpHeaders.TryAddWithoutValidation` method which does not check for CRLF characters in the header value. This means that any headers from a `RestSharp.RequestHeaders` object are added to the request in such a way that they are vulnerable to CRLF-injection. In general, CRLF-injection into a HTTP header (when using HTTP/1.1) means that one can inject additional HTTP headers or smuggle whole HTTP requests. If an application using the RestSharp library passes a user-controllable value through to a header, then that application becomes vulnerable to CRLF-injection. This is not necessarily a security issue for a command line application like the one above, but if such code were present in a web application then it becomes vulnerable to request splitting (as shown in the PoC) and thus Server Side Request Forgery. Strictly speaking this is a potential vulnerability in applications using RestSharp, not in RestSharp itself, but I would argue that at the very least there needs to be a warning about this behaviour in the RestSharp documentation. RestSharp has addressed this issue in version 112.0.0. All users are advised to upgrade. There are no known workarounds for this vulnerability.

The advisory is shared for download at github.com. This vulnerability was named CVE-2024-45302 since 08/26/2024. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available.

Upgrading to version 112.0.0 eliminates this vulnerability. Applying the patch 0fba5e727d241b1867bd71efc912594075c2934b is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Name

• RestSharp

Version

• 111

License

• open-source

Website

• Product: https://github.com/restsharp/RestSharp/

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Once again VulDB remains the best source for vulnerability data.

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