Researcher recovers AES key from encrypt-only firmware updates

ioactive.com5 min read

A vulnerability researcher details how to recover an AES symmetric key from an encrypt-only firmware update scheme by exploiting two separate oracles. First, a binary search leverages an error message indicating when a submitted value exceeds the RSA modulus to reconstruct the unpublished public key. Second, a Bleichenbacher padding oracle attack against PKCS#1 v1.5 uses manipulated ciphertexts to decrypt the target AES firmware key. Open article →