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The Hacker News - Cybersecurity News and Analysis: TSL Server

Let's Encrypt Revoking 3 Million TLS Certificates Issued Incorrectly Due to a Bug

Let's Encrypt Revoking 3 Million TLS Certificates Issued Incorrectly Due to a Bug
March 04, 2020Ravie Lakshmanan
The most popular free certificate signing authority Let's Encrypt is going to revoke more than 3 million TLS certificates within the next 24 hours that may have been issued wrongfully due to a bug in its Certificate Authority software. The bug, which Let's Encrypt confirmed on February 29 and was fixed two hours after discovery, impacted the way it checked the domain name ownership before issuing new TLS certificates. As a result, the bug opened up a scenario where a certificate could be issued even without adequately validating the holder's control of a domain name. The Certification Authority Authorization (CAA), an internet security policy, allows domain name holders to indicate to certificate authorities (CAs) whether or not they are authorized to issue digital certificates for a specific domain name. Let's Encrypt considers domain validation results good only for 30 days from the time of validation, after which it rechecks the CAA record authorizing t

ROBOT Attack: 19-Year-Old Bleichenbacher Attack On Encrypted Web Reintroduced

ROBOT Attack: 19-Year-Old Bleichenbacher Attack On Encrypted Web Reintroduced
December 12, 2017Swati Khandelwal
A 19-year-old vulnerability has been re-discovered in the RSA implementation from at least 8 different vendors—including F5, Citrix, and Cisco—that can give man-in-the-middle attackers access to encrypted messages. Dubbed ROBOT ( Return of Bleichenbacher's Oracle Attack ), the attack allows an attacker to perform RSA decryption and cryptographic operations using the private key configured on the vulnerable TLS servers. ROBOT attack is nothing but a couple of minor variations to the old Bleichenbacher attack on the RSA encryption protocol. First discovered in 1998 and named after Swiss cryptographer Daniel Bleichenbacher, the Bleichenbacher attack is a padding oracle attack on RSA-based PKCS#1 v1.5 encryption scheme used in SSLv2. Leveraging an adaptive chosen-ciphertext attack which occurred due to error messages by SSL servers for errors in the PKCS #1 1.5 padding, Bleichenbacher attack allows attackers to determine whether a decrypted message is correctly padded.
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