public key Archives

Verifying a DKIM TXT Record and Key Length

After reading the Wired story last week about Zachary Harris discovering a widespread vulnerability related to the use of weak cryptographic DKIM keys (less than 1024 bits) by companies like Google, eBay, Yahoo, Twitter and PayPal, and the subsequent CERT warning (VU#268267), I decided to write a quick tool to check DKIM TXT records and determine their key length:

DKIM KEY Checker ➜

This tool grabs your DKIM DNS TXT record and uses OpenSSL to parse the contained public key to determine its key length.

GitHub SSH Public Key Fingerprint Checking

A security vulnerability was discovered at GitHub back in 2012 that made it possible for an attacker to add new SSH keys to arbitrary GitHub user accounts. Although there was no known malicious activity using this exploit, they took the responsible step to email all their users that have SSH keys associated with their account to verify and approve them before they could be used to clone/pull/push repositories over SSH again.