Signature forgery via timing side channel

Observable timing discrepancy in verify in Net::OAuth before 0.33 allows remote attackers to forge OAuth signatures via timing analysis. The verify routines in the HMAC-SHA1, HMAC-SHA256, and PLAINTEXT signature methods compare the supplied and computed signatures with Perl's short-circuiting eq operator instead of a constant-time check, so rejection time leaks the length of the matching prefix; in PLAINTEXT mode, the compared value is the signature key itself. Reachability requires the ability to submit chosen OAuth messages and measure response timing, and the disclosed impact is bounded to signature recovery for HMAC methods and recovery of consumer_secret and token_secret for PLAINTEXT; RSA-SHA1 is not affected.