XOR Encrypted Payload Delivered via HTTP
This rule detects HTTP responses containing a payload that appears to be XOR encrypted. It specifically looks for a sequence of at least 200 bytes consisting of non-printable ASCII characters (0x01-0x1f and 0x7f-0xff) within the file data of an HTTP response flowing to the client. This pattern is indicative of XOR encryption, often used by malware to obfuscate its payload.
Suricata

