GNU » Gnutls : Security Vulnerabilities

A timing side-channel in the handling of RSA ClientKeyExchange messages was discovered in GnuTLS. This side-channel can be sufficient to recover the key encrypted in the RSA ciphertext across a network in a Bleichenbacher style attack. To achieve a successful decryption the attacker would need to send a large amount of specially crafted messages to the vulnerable server. By recovering the secret from the ClientKeyExchange message, the attacker would be able to decrypt the application data exchanged over that connection.

A vulnerability found in gnutls. This security flaw happens because of a double free error occurs during verification of pkcs7 signatures in gnutls_pkcs7_verify function.

A flaw was found in gnutls. A use after free issue in client_send_params in lib/ext/pre_shared_key.c may lead to memory corruption and other potential consequences.

A flaw was found in gnutls. A use after free issue in client sending key_share extension may lead to memory corruption and other consequences.

A NULL pointer dereference flaw was found in GnuTLS. As Nettle's hash update functions internally call memcpy, providing zero-length input may cause undefined behavior. This flaw leads to a denial of service after authentication in rare circumstances.

An issue was discovered in GnuTLS before 3.6.15. A server can trigger a NULL pointer dereference in a TLS 1.3 client if a no_renegotiation alert is sent with unexpected timing, and then an invalid second handshake occurs. The crash happens in the application's error handling path, where the gnutls_deinit function is called after detecting a handshake failure.

GnuTLS 3.6.x before 3.6.14 uses incorrect cryptography for encrypting a session ticket (a loss of confidentiality in TLS 1.2, and an authentication bypass in TLS 1.3). The earliest affected version is 3.6.4 (2018-09-24) because of an error in a 2018-09-18 commit. Until the first key rotation, the TLS server always uses wrong data in place of an encryption key derived from an application.

GnuTLS 3.6.x before 3.6.13 uses incorrect cryptography for DTLS. The earliest affected version is 3.6.3 (2018-07-16) because of an error in a 2017-10-06 commit. The DTLS client always uses 32 '\0' bytes instead of a random value, and thus contributes no randomness to a DTLS negotiation. This breaks the security guarantees of the DTLS protocol.

It was discovered in gnutls before version 3.6.7 upstream that there is an uninitialized pointer access in gnutls versions 3.6.3 or later which can be triggered by certain post-handshake messages.

A vulnerability was found in gnutls versions from 3.5.8 before 3.6.7. A memory corruption (double free) vulnerability in the certificate verification API. Any client or server application that verifies X.509 certificates with GnuTLS 3.5.8 or later is affected.

A Bleichenbacher type side-channel based padding oracle attack was found in the way gnutls handles verification of RSA decrypted PKCS#1 v1.5 data. An attacker who is able to run process on the same physical core as the victim process, could use this to extract plaintext or in some cases downgrade any TLS connections to a vulnerable server.

A cache-based side channel in GnuTLS implementation that leads to plain text recovery in cross-VM attack setting was found. An attacker could use a combination of "Just in Time" Prime+probe attack in combination with Lucky-13 attack to recover plain text using crafted packets.

It was found that the GnuTLS implementation of HMAC-SHA-384 was vulnerable to a Lucky thirteen style attack. Remote attackers could use this flaw to conduct distinguishing attacks and plain text recovery attacks via statistical analysis of timing data using crafted packets.

It was found that the GnuTLS implementation of HMAC-SHA-256 was vulnerable to a Lucky thirteen style attack. Remote attackers could use this flaw to conduct distinguishing attacks and plaintext-recovery attacks via statistical analysis of timing data using crafted packets.

GnuTLS before 2017-02-20 has an out-of-bounds write caused by an integer overflow and heap-based buffer overflow related to the cdk_pkt_read function in opencdk/read-packet.c. This issue (which is a subset of the vendor's GNUTLS-SA-2017-3 report) is fixed in 3.5.10.

GnuTLS version 3.5.12 and earlier is vulnerable to a NULL pointer dereference while decoding a status response TLS extension with valid contents. This could lead to a crash of the GnuTLS server application.

Multiple heap-based buffer overflows in the read_attribute function in GnuTLS before 3.3.26 and 3.5.x before 3.5.8 allow remote attackers to have unspecified impact via a crafted OpenPGP certificate.

Stack-based buffer overflow in the cdk_pk_get_keyid function in lib/opencdk/pubkey.c in GnuTLS before 3.3.26 and 3.5.x before 3.5.8 allows remote attackers to have unspecified impact via a crafted OpenPGP certificate.

The stream reading functions in lib/opencdk/read-packet.c in GnuTLS before 3.3.26 and 3.5.x before 3.5.8 allow remote attackers to cause a denial of service (out-of-memory error and crash) via a crafted OpenPGP certificate.

Double free vulnerability in the gnutls_x509_ext_import_proxy function in GnuTLS before 3.3.26 and 3.5.x before 3.5.8 allows remote attackers to have unspecified impact via crafted policy language information in an X.509 certificate with a Proxy Certificate Information extension.

The gnutls_ocsp_resp_check_crt function in lib/x509/ocsp.c in GnuTLS before 3.4.15 and 3.5.x before 3.5.4 does not verify the serial length of an OCSP response, which might allow remote attackers to bypass an intended certificate validation mechanism via vectors involving trailing bytes left by gnutls_malloc.

The "GNUTLS_KEYLOGFILE" environment variable in gnutls 3.4.12 allows remote attackers to overwrite and corrupt arbitrary files in the filesystem.

GnuTLS incorrectly validates the first byte of padding in CBC modes

Double free vulnerability in GnuTLS before 3.3.17 and 3.4.x before 3.4.4 allows remote attackers to cause a denial of service via a long DistinguishedName (DN) entry in a certificate.

Double free vulnerability in lib/x509/x509_ext.c in GnuTLS before 3.3.14 allows remote attackers to cause a denial of service or possibly have unspecified other impact via a crafted CRL distribution point.