Many threats that are common to distributed systems are common to Web services as well. There are a few specific threats associated with the Web services processing model, such as:
- Message replays: An attacker may re-play an entire message or a part of a SOAP message.
- Man in the middle attack: An attacker may view and modify a SOAP message without the knowledge of either sender or the receiver.
- Identity spoofing: An attempt to construct credentials that seems to be valid but not.
- Denial of Service (DOS) attacks: An attempt to make a system expend its resources so that valid requests cannot access a service.
- Message alteration: An attempt to alter a message compromising its integrity.
- Confidentiality issues: Access to confidential information within a message by unauthorized parties.
Dimuthu wrote an interesting post about how to prevent replay attacks using WSF/PHP. He also shows how to detect them using WS-Addressing and WS-Username token headers.
Federico Cargnelutti 