OpenSSL v1.0.2.o Release NotesRelease Date: 2018-08-14 // about 3 years ago
- Client DoS due to large DH parameter
During key agreement in a TLS handshake using a DH(E) based ciphersuite a malicious server can send a very large prime value to the client. This will cause the client to spend an unreasonably long period of time generating a key for this prime resulting in a hang until the client has finished. This could be exploited in a Denial Of Service attack.
This issue was reported to OpenSSL on 5th June 2018 by Guido Vranken [CVE-2018-0732]
- Cache timing vulnerability in RSA Key Generation
The OpenSSL RSA Key generation algorithm has been shown to be vulnerable to a cache timing side channel attack. An attacker with sufficient access to mount cache timing attacks during the RSA key generation process could recover the private key.
This issue was reported to OpenSSL on 4th April 2018 by Alejandro Cabrera Aldaya, Billy Brumley, Cesar Pereida Garcia and Luis Manuel Alvarez Tapia. [CVE-2018-0737]
- Make EVP_PKEY_asn1_new() a bit stricter about its input. A NULL pem_str parameter is no longer accepted, as it leads to a corrupt table. NULL pem_str is reserved for alias entries only.
- Revert blinding in ECDSA sign and instead make problematic addition length-invariant. Switch even to fixed-length Montgomery multiplication.
- Change generating and checking of primes so that the error rate of not being prime depends on the intended use based on the size of the input. For larger primes this will result in more rounds of Miller-Rabin. The maximal error rate for primes with more than 1080 bits is lowered to 2-128.
Kurt Roeckx, Annie Yousar
- Increase the number of Miller-Rabin rounds for DSA key generating to 64.
- Add blinding to ECDSA and DSA signatures to protect against side channel attacks discovered by Keegan Ryan (NCC Group).
- When unlocking a pass phrase protected PEM file or PKCS#8 container, we now allow empty (zero character) pass phrases.
- Certificate time validation (X509_cmp_time) enforces stricter compliance with RFC 5280. Fractional seconds and timezone offsets are no longer allowed.