I’ve been looking into how common "callback URL" parameters can be weaponized to exfiltrate sensitive cloud metadata. A common payload I'm seeing in logs looks like this: ?callbackUrl=file:///home/*/.aws/credentials 🔍 What is happening? Attackers use the
Recommended urgent policy changes
Local File URI Callback for Credential Delivery callback-url-file-3A-2F-2F-2Fhome-2F-2A-2F.aws-2Fcredentials
: If you must support multiple subdomains, use a strict regular expression that prevents encoded characters like %3A ( : ) or %2F ( / ) from being used to bypass filters. 2. Harden AWS Credential Access I’ve been looking into how common "callback URL"
Exposure of these keys bypasses the entire perimeter security of the application, granting direct programmatic API access to the underlying AWS cloud infrastructure associated with that specific server deployment. Callback URLs - Beeceptor If successful, an attacker gains full programmatic access
: Critical . If successful, an attacker gains full programmatic access to your AWS resources associated with that server's IAM role or user.