SB2021020202 - IBM AIX update for OpenSSL
Published: February 2, 2021
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 2 secuirty vulnerabilities.
1) Raccoon attack (CVE-ID: CVE-2020-1968)
The vulnerability allows a remote attacker to gain access to potentially sensitive information.
The vulnerability exists due to a timing flaw in the TLS specification. A remote attacker can compute the pre-master secret in connections which have used a Diffie-Hellman (DH) based ciphersuite and eavesdrop on all encrypted communications sent over that TLS connection.
Note: The attack can only be exploited if an implementation re-uses a DH secret across multiple TLS connections.
2) NULL pointer dereference (CVE-ID: CVE-2020-1971)
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to a NULL pointer dereference error. A remote attacker can trigger denial of service conditions 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.
Remediation
Install update from vendor's website.