GHSA-f8m2-889x-vw4x: Infoleak
Impact A client configured with a client-wide realm (a Realm set on the config builder rather than on an individual request) and following redirects could re-send those credentials to a redirect target on a different origin. The redirect code strips the per-exchange realm, but when the target answered 401 the credentials were re-derived from the client config, handing Basic or Digest credentials, or a Negotiate or NTLM token, to an attacker controlled origin. This is a residual of the earlier cross-origin credential leak advisories, whose strip this bypassed.
Affected versions 3.x: 3.0.9 through 3.0.11 2.x: 2.14.5 through 2.16.0
Releases below those floors are covered by the earlier advisories GHSA-cmxv-58fp-fm3g and GHSA-fmxf-pm6p-7xgm: the cross-origin strip that this issue bypasses did not exist yet, so the leak there is the original one rather than this residual.
Patches Fixed in 3.0.12 on the 3.x line and in 2.16.1 on the 2.x line. The realm is taken from the per-exchange state that the redirect already cleared, rather than being re-derived from the client configuration.
Workarounds Set the Realm on the individual request instead of on the client configuration. A per-request realm is stripped correctly on a cross-origin redirect while still authenticating same-origin, so this is a complete workaround with no loss of function. Turning off follow-redirects also avoids it. Note that setStripAuthorizationOnRedirect(true) is not a workaround: it forces the strip, but the configuration fallback re-derived the realm regardless.
Details The interceptor read the realm as the request's realm or, failing that, the client configuration's realm, which re-attached the config realm after the redirect strip had cleared it. It now reads the realm held on the response future. See also GHSA-cmxv-58fp-fm3g and GHSA-fmxf-pm6p-7xgm.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
maven/org.asynchttpclient:async-http-clientto a version that resolves this vulnerability.Fixed in 2.16.1 - Upgrade
Upgrade
maven/org.asynchttpclient:async-http-clientto a version that resolves this vulnerability.Fixed in 3.0.12 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 2.16.1 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 3.0.12 - Configuration
Set the Realm on the individual request rather than on the client configuration builder (client-wide realm).
client configuration Realm = set on the individual request instead of on the client configuration - Configuration
Disable follow-redirects to avoid re-sending credentials after redirects.
redirect handling followRedirects = false
Event History
Frequently Asked Questions
Which deployments are exposed to this issue?
Deployments using async-http-client versions 3.0.9 through 3.0.11 or 2.14.5 through 2.16.0 are affected when a Realm is configured client-wide and the client follows redirects. The issue can expose Basic or Digest credentials, or Negotiate or NTLM tokens.
What must occur for credentials to be disclosed?
The client must follow a redirect to a different origin, and that redirect target must respond with HTTP 401. In that situation, the client can re-derive credentials from the client-wide configuration and send them to an attacker-controlled origin.
Are configurations that set authentication per request affected?
The provided workaround indicates that setting the Realm on each individual request avoids this issue. The vulnerable behavior is specifically tied to a Realm configured on the client configuration builder rather than on an individual request.
What can be done if upgrading is not immediately possible?
Set the Realm on individual requests instead of on the client configuration. Permanent fixes are available in version 3.0.12 for the 3.x line and 2.16.1 for the 2.x line.