Stay Secure with the Latest Linux Advisories

security advisorydenial of servicecritical

Mageia 8: Critical OpenSSL DoS Vulnerabilities Identified in 2021-0176

An OpenSSL TLS server may crash if sent a maliciously crafted renegotiation ClientHello message from a client. If a TLSv1.2 renegotiation ClientHello omits the signature_algorithms extension (where it was present in the initial ClientHello), but includes a signature_algorithms_cert extension then a NULL pointer dereference will result, leading to a crash and a denial of service . MGASA-2021-0176 - Updated openssl packages fix security vulnerability Publication date: 05 Apr 2021 URL: https://advisories.mageia.org/MGASA-2021-0176.html Type: security Affected Mageia releases: 8 CVE: CVE-2021-3449, CVE-2021-3450 An OpenSSL TLS server may crash if sent a maliciously crafted renegotiation ClientHello message from a client. If a TLSv1.2 renegotiation ClientHello omits the signature_algorithms extension (where it was present in the initial ClientHello), but includes a signature_algorithms_cert extension then a NULL pointer dereference will result, leading to a crash and a denial of service attack. A server is only vulnerable if it has TLSv1.2 and renegotiation enabled (which is the default configuration). OpenSSL TLS clients are not impacted by this issue. (CVE-2021-3449). The X509_V_FLAG_X509_STRICT flag enables additional security checks of the certificates present in a certificate chain. It is not set by default. Starting from OpenSSL version 1.1.1h a check to disallow certificates in the chain that have explicitly encoded elliptic curve parameters was added as an additional strict check. An error in the implementation of this check meant that the result of a previous check to confirm that certificates in the chain are valid CA certificates was overwritten. This effectively bypasses the check that non-CA certificates must not be able to issue other certificates. If a "purpose" has been configured then there is a subsequent opportunity for checks that the certificate is a valid CA. All of the named "purpose" values implemented in libcrypto perform this check. Therefore, where a purpose is set thecertificate chain will still be rejected even when the strict flag has been used. A purpose is set by default in libssl client and server certificate verification routines, but it can be overridden or removed by an application. In order to be affected, an application must explicitly set the X509_V_FLAG_X509_STRICT verification flag and either not set a purpose for the certificate verification or, in the case of TLS client or server applications, override the default purpose. (CVE-2021-3450). References: - https://bugs.mageia.org/show_bug.cgi?id=28640 - https://openssl-library.org/news/secadv/20210325.txt - https://www.cve.org/CVERecord?id=CVE-2021-3449 - https://www.cve.org/CVERecord?id=CVE-2021-3450 SRPMS: - 8/core/openssl-1.1.1k-1.mga8 . Mageia's latest OpenSSL updates tackle critical vulnerabilities and safeguard against possible Denial of Service threats.. OpenSSL Update,Mageia Advisory,TLS Security,Denial Of Service,Security Fixes. . Severity: Critical. LinuxSecurity.com Team

Apr 05, 2021 •Critical Mageia