CVE-2014-1959

lib/x509/verify.c en GnuTLS anterior a 3.1.21 y 3.2.x anterior a 3.2.11 trata certificados X.509 de versión 1 como CAs intermedios, lo que permite a atacantes remotos evadir restricciones mediante el aprovechamiento de un certificado X.509 V1 de un CA confiable para emitir certificados nuevos.

Suman Jana reported a vulnerability that affects the certificate verification functions of gnutls 3.1.x and gnutls 3.2.x. A version 1 intermediate certificate will be considered as a CA certificate by default. It was discovered that GnuTLS did not correctly handle certain errors that could occur during the verification of an X.509 certificate, causing it to incorrectly report a successful verification. An attacker could use this flaw to create a specially crafted certificate that could be accepted by GnuTLS as valid for a site chosen by the attacker. A NULL pointer dereference flaw was discovered in GnuTLS's gnutls_x509_dn_oid_name(). The function, when called with the GNUTLS_X509_DN_OID_RETURN_OID flag, should not return NULL to its caller. However, it could previously return NULL when parsed X.509 certificates included specific OIDs. A flaw was found in the way GnuTLS parsed session ids from Server Hello packets of the TLS/SSL handshake. A malicious server could use this flaw to send an excessively long session id value and trigger a buffer overflow in a connecting TLS/SSL client using GnuTLS, causing it to crash or, possibly, execute arbitrary code. An out-of-bounds memory write flaw was found in the way GnuTLS parsed certain ECC certificates or certificate signing requests. A malicious user could create a specially crafted ECC certificate or a certificate signing request that, when processed by an application compiled against GnuTLS (for example, certtool), could cause that application to crash or execute arbitrary code with the permissions of the user running the application.