CVE-2020-1968

The Raccoon attack exploits a flaw in the TLS specification which can lead to an attacker being able to compute the pre-master secret in connections which have used a Diffie-Hellman (DH) based ciphersuite. In such a case this would result in the attacker being able to eavesdrop on all encrypted communications sent over that TLS connection. The attack can only be exploited if an implementation re-uses a DH secret across multiple TLS connections. Note that this issue only impacts DH ciphersuites and not ECDH ciphersuites. This issue affects OpenSSL 1.0.2 which is out of support and no longer receiving public updates. OpenSSL 1.1.1 is not vulnerable to this issue. Fixed in OpenSSL 1.0.2w (Affected 1.0.2-1.0.2v).

The Raccoon attack exploits a flaw in the TLS specification which can lead to an attacker being able to compute the pre-master secret in connections which have used a Diffie-Hellman (DH) based ciphersuite. In such a case this would result in the attacker being able to eavesdrop on all encrypted communications sent over that TLS connection. The attack can only be exploited if an implementation re-uses a DH secret across multiple TLS connections. Note that this issue only impacts DH ciphersuites and not ECDH ciphersuites. (CVE-2020-1968)

The X.509 GeneralName type is a generic type for representing different types of names. One of those name types is known as EDIPartyName. OpenSSL provides a function GENERAL_NAME_cmp which compares different instances of a GENERAL_NAME to see if they are equal or not. This function behaves incorrectly when both GENERAL_NAMEs contain an EDIPARTYNAME. A NULL pointer dereference and a crash may occur leading to a possible denial of service attack. OpenSSL itself uses the GENERAL_NAME_cmp function for two purposes:

1. Comparing CRL distribution point names between an available CRL and a CRL distribution point embedded in an X509 certificate
2. When verifying that a timestamp response token signer matches the timestamp authority name (exposed via the API functions TS_RESP_verify_response and TS_RESP_verify_token) If an attacker can control both items being compared then that attacker could trigger a crash. For example if the attacker can trick a client or server into checking a malicious certificate against a malicious CRL then this may occur. Note that some applications automatically download CRLs based on a URL embedded in a certificate. This checking happens prior to the signatures on the certificate and CRL being verified. OpenSSL's s_server, s_client and verify tools have support for the "-crl_download" option which implements automatic CRL downloading and this attack has been demonstrated to work against those tools. Note that an unrelated bug means that affected versions of OpenSSL cannot parse or construct correct encodings of EDIPARTYNAME. However it is possible to construct a malformed EDIPARTYNAME that OpenSSL's parser will accept and hence trigger this attack. (CVE-2020-1971)

This update for openssl fixes the following issues:

• CVE-2020-1968: Introduced hardening against the Raccoon attack by always generating fresh DH keys and never reuse them across multiple TLS connections (bsc#1176331).

This update for openssl1 fixes the following issues:

• CVE-2020-1968: Introduced hardening against the Raccoon attack by always generating fresh DH keys and never reuse them across multiple TLS connections (bsc#1176331).

This update for compat-openssl098 fixes the following issues:

• CVE-2020-1968: Introduced hardening against the Raccoon attack by always generating fresh DH keys and never reuse them across multiple TLS connections (bsc#1176331).

Robert Merget, Marcus Brinkmann, Nimrod Aviram, and Juraj Somorovsky discovered that certain Diffie-Hellman ciphersuites in the TLS specification and implemented by OpenSSL contained a flaw. A remote attacker could possibly use this issue to eavesdrop on encrypted communications. This was fixed in this update by removing the insecure ciphersuites from OpenSSL. (CVE-2020-1968)

Cesar Pereida García, Sohaib ul Hassan, Nicola Tuveri, Iaroslav Gridin, Alejandro Cabrera Aldaya, and Billy Brumley discovered that OpenSSL incorrectly handled ECDSA signatures. An attacker could possibly use this issue to perform a timing side-channel attack and recover private ECDSA keys. This issue only affected Ubuntu 18.04 LTS. (CVE-2019-1547)

Guido Vranken discovered that OpenSSL incorrectly performed the x86_64 Montgomery squaring procedure. While unlikely, a remote attacker could possibly use this issue to recover private keys. This issue only affected Ubuntu 18.04 LTS. (CVE-2019-1551)

Bernd Edlinger discovered that OpenSSL incorrectly handled certain decryption functions. In certain scenarios, a remote attacker could possibly use this issue to perform a padding oracle attack and decrypt traffic. This issue only affected Ubuntu 18.04 LTS. (CVE-2019-1563)

Robert Merget, Marcus Brinkmann, Nimrod Aviram, and Juraj Somorovsky discovered that certain Diffie-Hellman ciphersuites in the TLS specification and implemented by OpenSSL contained a flaw. A remote attacker could possibly use this issue to eavesdrop on encrypted communications. This was fixed in this update by removing the insecure ciphersuites from OpenSSL. (CVE-2020-1968)

Paul Kehrer discovered that OpenSSL incorrectly handled certain input lengths in EVP functions. A remote attacker could possibly use this issue to cause OpenSSL to crash, resulting in a denial of service. (CVE-2021-23840)

Elison Niven discovered that OpenSSL incorrectly handled the c_rehash script. A local attacker could possibly use this issue to execute arbitrary commands when c_rehash is run. (CVE-2022-1292)

Chancen and Daniel Fiala discovered that OpenSSL incorrectly handled the c_rehash script. A local attacker could possibly use this issue to execute arbitrary commands when c_rehash is run. (CVE-2022-2068)

It was discovered that OpenSSL incorrectly handled excessively large Diffie-Hellman parameters. An attacker could possibly use this issue to cause a denial of service. (CVE-2023-3446)

Bahaa Naamneh discovered that OpenSSL incorrectly handled certain malformed PKCS12 files. A remote attacker could possibly use this issue to cause OpenSSL to crash, resulting in a denial of service. (CVE-2024-0727)