Know every vulnerabilitybefore it knows you.
DevGuard continuously monitors your dependencies and alerts you when CVEs like this one affect your stack — with real-time threat intelligence built for developers.
GHSA-6wcg-mqvh-fcvg
github.com/techarohq/anubisAny HTTP client can bypass Anubis bot protection on the default configuration by adding a single request header. No challenge needs to be solved. Affected versions: v1.22.0 through v1.25.0 (introduced in commit d1d631a, PR #1015)
The root cause is in lib/policy/checker.go, PathChecker.Check():
func (pc *PathChecker) Check(r *http.Request) (bool, error) {
originalUrl := r.Header.Get("X-Original-URI")
if originalUrl != "" {
if pc.regexp.MatchString(originalUrl) {
return true, nil
}
}
if pc.regexp.MatchString(r.URL.Path) {
return true, nil
}
return false, nil
}
The header value comes directly from the client request. The middleware chain never strips it. In reverse proxy mode an attacker fully controls it.
The default policy imports data/common/keep-internet-working.yaml, which contains path-only ALLOW rules with no other conditions:
- name: well-known
path_regex: ^/\.well-known/.*$
action: ALLOW
When X-Original-URI matches one of those regexes, the rule fires as ALLOW and the request is forwarded upstream without any challenge or JWT check.
Proof of concept
Normal request, gets challenged:
curl -s https://anubis.techaro.lol/ | grep -o "<title>.*</title>"
Bypass, gets upstream content:
curl -s -H "X-Original-URI: /.well-known/x" https://anubis.techaro.lol/ | grep -o "<title>.*</title>"
The first command returns the Anubis challenge page title. The second returns the real site title directly, with no cookie set and no challenge issued. Verified live against anubis.techaro.lol.
Suggested fix
The fix should probably be to strip the header from incoming client requests in the middleware chain before policy evaluation. In auth_request mode the header is set by the proxy after Anubis processes the middleware, so stripping it at ingress does not break that deployment mode.
Upload your own SBOM in CycloneDX 1.6 or higher (JSON) directly here to check your vulnerabilities.
Drag and drop some file here, or click to select
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The vulnerability can affect other systems as well, not just the initial system. There is a low impact on the confidentiality of the information.
Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
Browse More
Continuously monitor your dependencies and get alerted when vulnerabilities like this one affect your stack.
Checkout DevGuard