SSL: OpenSSL TLS server Renegotiation Handling NULL Pointer Dereference

This signature detects attempts to exploit a known vulnerability against OpenSSL. A successful attack can result in a denial-of-service condition.

Extended Description

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. All OpenSSL 1.1.1 versions are affected by this issue. Users of these versions should upgrade to OpenSSL 1.1.1k. OpenSSL 1.0.2 is not impacted by this issue. Fixed in OpenSSL 1.1.1k (Affected 1.1.1-1.1.1j).

Affected Products

Nodejs node.js

References

CVE: CVE-2021-3449

Short Name

SSL:OPENSSL-TLS-SRVR-HNDLNG-DOS

Severity

Major

Recommended

False

Recommended Action

Drop

SSL: OpenSSL TLS server Renegotiation Handling NULL Pointer Dereference

Extended Description

Affected Products

References

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