German computer scientists have cracked components of an encryption system used to securely exchange data between e-commerce and banking systems.
Boffins from the Ruhr University of Bochum (RUB) have devised a technique partly based on analysing error messages returned when carefully modified cipher text is submitted to a web service. By analysing the results of a sequence of error messages it is possible to decrypt encrypted XML-based data elements, H Security reports.
The official W3C XML encryption specification is designed to allow the secure transmission of information between different e-commerce and financial systems. The attack is limited to where AES is used for encryption in the cipher-block chaining (CBC) mode; other techniques, such as using an RSA key and X.509 certificates, are not susceptible.
The cryptoboffins argue their research shows the standard is insecure and needs to be updated. The researchers, Juraj Somorovsky and Tibor Jager, plan to present their research at the ACM Conference on Computer and Communications Security (ACM CCS 2011) in Chicago.
IBM, Microsoft, and Red Hat Linux use the technology for various web services applications. Each has been notified by the RUB team of its findings (summarised in German here). ®