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Diffstat (limited to 'CHANGES')
| -rw-r--r-- | CHANGES | 160 |
1 files changed, 160 insertions, 0 deletions
@@ -2,6 +2,166 @@ OpenSSL CHANGES _______________ + Changes between 1.0.2h and 1.0.2i [22 Sep 2016] + + *) OCSP Status Request extension unbounded memory growth + + A malicious client can send an excessively large OCSP Status Request + extension. If that client continually requests renegotiation, sending a + large OCSP Status Request extension each time, then there will be unbounded + memory growth on the server. This will eventually lead to a Denial Of + Service attack through memory exhaustion. Servers with a default + configuration are vulnerable even if they do not support OCSP. Builds using + the "no-ocsp" build time option are not affected. + + This issue was reported to OpenSSL by Shi Lei (Gear Team, Qihoo 360 Inc.) + (CVE-2016-6304) + [Matt Caswell] + + *) In order to mitigate the SWEET32 attack, the DES ciphers were moved from + HIGH to MEDIUM. + + This issue was reported to OpenSSL Karthikeyan Bhargavan and Gaetan + Leurent (INRIA) + (CVE-2016-2183) + [Rich Salz] + + *) OOB write in MDC2_Update() + + An overflow can occur in MDC2_Update() either if called directly or + through the EVP_DigestUpdate() function using MDC2. If an attacker + is able to supply very large amounts of input data after a previous + call to EVP_EncryptUpdate() with a partial block then a length check + can overflow resulting in a heap corruption. + + The amount of data needed is comparable to SIZE_MAX which is impractical + on most platforms. + + This issue was reported to OpenSSL by Shi Lei (Gear Team, Qihoo 360 Inc.) + (CVE-2016-6303) + [Stephen Henson] + + *) Malformed SHA512 ticket DoS + + If a server uses SHA512 for TLS session ticket HMAC it is vulnerable to a + DoS attack where a malformed ticket will result in an OOB read which will + ultimately crash. + + The use of SHA512 in TLS session tickets is comparatively rare as it requires + a custom server callback and ticket lookup mechanism. + + This issue was reported to OpenSSL by Shi Lei (Gear Team, Qihoo 360 Inc.) + (CVE-2016-6302) + [Stephen Henson] + + *) OOB write in BN_bn2dec() + + The function BN_bn2dec() does not check the return value of BN_div_word(). + This can cause an OOB write if an application uses this function with an + overly large BIGNUM. This could be a problem if an overly large certificate + or CRL is printed out from an untrusted source. TLS is not affected because + record limits will reject an oversized certificate before it is parsed. + + This issue was reported to OpenSSL by Shi Lei (Gear Team, Qihoo 360 Inc.) + (CVE-2016-2182) + [Stephen Henson] + + *) OOB read in TS_OBJ_print_bio() + + The function TS_OBJ_print_bio() misuses OBJ_obj2txt(): the return value is + the total length the OID text representation would use and not the amount + of data written. This will result in OOB reads when large OIDs are + presented. + + This issue was reported to OpenSSL by Shi Lei (Gear Team, Qihoo 360 Inc.) + (CVE-2016-2180) + [Stephen Henson] + + *) Pointer arithmetic undefined behaviour + + Avoid some undefined pointer arithmetic + + A common idiom in the codebase is to check limits in the following manner: + "p + len > limit" + + Where "p" points to some malloc'd data of SIZE bytes and + limit == p + SIZE + + "len" here could be from some externally supplied data (e.g. from a TLS + message). + + The rules of C pointer arithmetic are such that "p + len" is only well + defined where len <= SIZE. Therefore the above idiom is actually + undefined behaviour. + + For example this could cause problems if some malloc implementation + provides an address for "p" such that "p + len" actually overflows for + values of len that are too big and therefore p + len < limit. + + This issue was reported to OpenSSL by Guido Vranken + (CVE-2016-2177) + [Matt Caswell] + + *) Constant time flag not preserved in DSA signing + + Operations in the DSA signing algorithm should run in constant time in + order to avoid side channel attacks. A flaw in the OpenSSL DSA + implementation means that a non-constant time codepath is followed for + certain operations. This has been demonstrated through a cache-timing + attack to be sufficient for an attacker to recover the private DSA key. + + This issue was reported by César Pereida (Aalto University), Billy Brumley + (Tampere University of Technology), and Yuval Yarom (The University of + Adelaide and NICTA). + (CVE-2016-2178) + [César Pereida] + + *) DTLS buffered message DoS + + In a DTLS connection where handshake messages are delivered out-of-order + those messages that OpenSSL is not yet ready to process will be buffered + for later use. Under certain circumstances, a flaw in the logic means that + those messages do not get removed from the buffer even though the handshake + has been completed. An attacker could force up to approx. 15 messages to + remain in the buffer when they are no longer required. These messages will + be cleared when the DTLS connection is closed. The default maximum size for + a message is 100k. Therefore the attacker could force an additional 1500k + to be consumed per connection. By opening many simulataneous connections an + attacker could cause a DoS attack through memory exhaustion. + + This issue was reported to OpenSSL by Quan Luo. + (CVE-2016-2179) + [Matt Caswell] + + *) DTLS replay protection DoS + + A flaw in the DTLS replay attack protection mechanism means that records + that arrive for future epochs update the replay protection "window" before + the MAC for the record has been validated. This could be exploited by an + attacker by sending a record for the next epoch (which does not have to + decrypt or have a valid MAC), with a very large sequence number. This means + that all subsequent legitimate packets are dropped causing a denial of + service for a specific DTLS connection. + + This issue was reported to OpenSSL by the OCAP audit team. + (CVE-2016-2181) + [Matt Caswell] + + *) Certificate message OOB reads + + In OpenSSL 1.0.2 and earlier some missing message length checks can result + in OOB reads of up to 2 bytes beyond an allocated buffer. There is a + theoretical DoS risk but this has not been observed in practice on common + platforms. + + The messages affected are client certificate, client certificate request + and server certificate. As a result the attack can only be performed + against a client or a server which enables client authentication. + + This issue was reported to OpenSSL by Shi Lei (Gear Team, Qihoo 360 Inc.) + (CVE-2016-6306) + [Stephen Henson] + Changes between 1.0.2g and 1.0.2h [3 May 2016] *) Prevent padding oracle in AES-NI CBC MAC check |