Red Hat Enterprise Linux 8.1 update for openssl

1) NULL pointer dereference

EUVDB-ID: #VU51733

Risk: Medium

CVSSv4.0: 7.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P/U:Green]

CVE-ID: CVE-2021-3449

CWE-ID: CWE-476 - NULL Pointer Dereference

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a NULL pointer dereference error when processing TLSv1.2 renegotiations. A remote attacker can send a maliciously crafted renegotiation ClientHello message, which omits the signature_algorithms extension but includes a signature_algorithms_cert extension, trigger a NULL pointer dereference error and crash the server.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for ARM 64 - Extended Update Support: 8.1

Red Hat Enterprise Linux for Power, little endian - Extended Update Support: 8.1

Red Hat Enterprise Linux for IBM z Systems - Extended Update Support: 8.1

Red Hat Enterprise Linux for x86_64 - Extended Update Support: 8.1

Red Hat Enterprise Linux Server for x86_64 - Update Services for SAP Solutions: 8.1

Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions: 8.1

openssl (Red Hat package): before 1.1.1c-5.el8_1

CPE2.3

• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_arm_64_-_extended_update_support:8.1:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_power_little_endian_-_extended_update_support:8.1:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_ibm_z_systems_-_extended_update_support:8.1:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_x86_64_-_extended_update_support:8.1:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_server_-_update_services_for_sap_solutions:8.1:*:*:*:*:*:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_server_for_ibm_power_le_-_update_services_for_sap_solutions:8.1:*:*:*:*:*:*:*
• cpe:2.3:o:red_hat:openssl_redhat_package:*:*:*:*:*:red_hat_enterprise_linux:*:*

External links

https://access.redhat.com/errata/RHSA-2021:1131

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.