OpenSSL 0.9.8y/1.x/1.0.1e man-in-the-middle attack 0day

2014-01-05 / 2014-01-06
Risk: Medium
Local: No
Remote: Yes
CWE: CWE-310


CVSS Base Score: 5.8/10
Impact Subscore: 4.9/10
Exploitability Subscore: 8.6/10
Exploit range: Remote
Attack complexity: Medium
Authentication: No required
Confidentiality impact: None
Integrity impact: Partial
Availability impact: Partial

For DTLS we might need to retransmit messages from the previous session so keep a copy of write context in DTLS retransmission buffers instead of replacing it after sending CCS. CVE-2013-6450. diff --git a/CHANGES b/CHANGES index cfaebba..173be24 100644 (file) --- a/CHANGES +++ b/CHANGES @@ -4,6 +4,11 @@ Changes between 1.0.1e and 1.0.1f [xx XXX xxxx] + *) Keep original DTLS digest and encryption contexts in retransmission + structures so we can use the previous session parameters if they need + to be resent. (CVE-2013-6450) + [Steve Henson] + *) Add option SSL_OP_SAFARI_ECDHE_ECDSA_BUG (part of SSL_OP_ALL) which avoids preferring ECDHE-ECDSA ciphers when the client appears to be Safari on OS X. Safari on OS X 10.8..10.8.3 advertises support for diff --git a/ssl/d1_both.c b/ssl/d1_both.c index 65ec001..7a5596a 100644 (file) --- a/ssl/d1_both.c +++ b/ssl/d1_both.c @@ -214,6 +214,12 @@ dtls1_hm_fragment_new(unsigned long frag_len, int reassembly) static void dtls1_hm_fragment_free(hm_fragment *frag) { + + if (frag->msg_header.is_ccs) + { + EVP_CIPHER_CTX_free(frag->msg_header.saved_retransmit_state.enc_write_ctx); + EVP_MD_CTX_destroy(frag->msg_header.saved_retransmit_state.write_hash); + } if (frag->fragment) OPENSSL_free(frag->fragment); if (frag->reassembly) OPENSSL_free(frag->reassembly); OPENSSL_free(frag); diff --git a/ssl/ssl_locl.h b/ssl/ssl_locl.h index 96ce9a7..e485907 100644 (file) --- a/ssl/ssl_locl.h +++ b/ssl/ssl_locl.h @@ -621,6 +621,8 @@ extern SSL3_ENC_METHOD TLSv1_enc_data; extern SSL3_ENC_METHOD SSLv3_enc_data; extern SSL3_ENC_METHOD DTLSv1_enc_data; +#define SSL_IS_DTLS(s) (s->method->version == DTLS1_VERSION) + #define IMPLEMENT_tls_meth_func(version, func_name, s_accept, s_connect, \ s_get_meth) \ const SSL_METHOD *func_name(void) \ diff --git a/ssl/t1_enc.c b/ssl/t1_enc.c index 72015f5..56db834 100644 (file) --- a/ssl/t1_enc.c +++ b/ssl/t1_enc.c @@ -414,15 +414,20 @@ int tls1_change_cipher_state(SSL *s, int which) s->mac_flags |= SSL_MAC_FLAG_WRITE_MAC_STREAM; else s->mac_flags &= ~SSL_MAC_FLAG_WRITE_MAC_STREAM; - if (s->enc_write_ctx != NULL) + if (s->enc_write_ctx != NULL && !SSL_IS_DTLS(s)) reuse_dd = 1; - else if ((s->enc_write_ctx=OPENSSL_malloc(sizeof(EVP_CIPHER_CTX))) == NULL) + else if ((s->enc_write_ctx=EVP_CIPHER_CTX_new()) == NULL) goto err; - else - /* make sure it's intialized in case we exit later with an error */ - EVP_CIPHER_CTX_init(s->enc_write_ctx); dd= s->enc_write_ctx; - mac_ctx = ssl_replace_hash(&s->write_hash,NULL); + if (SSL_IS_DTLS(s)) + { + mac_ctx = EVP_MD_CTX_create(); + if (!mac_ctx) + goto err; + s->write_hash = mac_ctx; + } + else + mac_ctx = ssl_replace_hash(&s->write_hash,NULL); #ifndef OPENSSL_NO_COMP if (s->compress != NULL) {

References:

http://git.openssl.org/gitweb/?p=openssl.git;a=commit;h=34628967f1e65dc8f34e000f0f5518e21afbfc7b
https://security-tracker.debian.org/tracker/CVE-2013-6450


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