Red Hat Enterprise Linux 7 update for ruby

1) Security restrictions bypass

EUVDB-ID: #VU15725

Risk: Low

CVSSv4.0: 4.6 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2018-16396

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

The vulnerability allows a remote attacker to bypass security restrictions on the target system.

The weakness exists due to the tainted flags are not propagated with the B, b, H, and h directives. A remote attacker can supply inputs by Array#pack and/or String#unpack with these directives and checks the reliability with tainted flags and cause the check to be wrong to bypass security restrictions and conduct further attacks.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

ruby (Red Hat package): 2.0.0.648-34.el7_6 - 2.0.0.648-37.el7_6

Red Hat Enterprise Linux for x86_64 - Extended Update Support: 7.6

Red Hat Enterprise Linux Server for x86_64 - Update Services for SAP Solutions: 7.6

Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions: 7.6

Red Hat Enterprise Linux Server - TUS: 7.6

Red Hat Enterprise Linux for Power, little endian - Extended Update Support: 7.6

Red Hat Enterprise Linux EUS Compute Node: 7.6

Red Hat Enterprise Linux for Power, big endian - Extended Update Support: 7.6

Red Hat Enterprise Linux for IBM z Systems - Extended Update Support: 7.6

Red Hat Enterprise Linux Server - AUS: 7.6

Red Hat Enterprise Linux for IBM System z (Structure A): 7.0

Red Hat Enterprise Linux for Power 9: 7.0

Red Hat Enterprise Linux for ARM 64: 7.0

CPE2.3

• cpe:2.3:a:red_hat:ruby_redhat_package:2.0.0.648-34.el7_6:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:a:red_hat:ruby_redhat_package:2.0.0.648-35.el7_6:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:a:red_hat:ruby_redhat_package:2.0.0.648-36.el7_6:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_x86_64_-_extended_update_support:7.6:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:a:red_hat:red_hat_enterprise_linux_server_-_update_services_for_sap_solutions:7.6:*:*:*:*:*:*:*
• cpe:2.3:a:red_hat:red_hat_enterprise_linux_server_for_ibm_power_le_-_update_services_for_sap_solutions:7.6:*:*:*:*:*:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_server_-_tus:7.6:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_power_little_endian_-_extended_update_support:7.6:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_eus_compute_node:7.6:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_power_big_endian_-_extended_update_support:7.6:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_ibm_z_systems_-_extended_update_support:7.6:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_server_-_aus:7.6:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_ibm_system_z_structure_a:7.0:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_power_9:7.0:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_arm_64:7.0:*:*:*:*:red_hat_enterprise_linux:*:*

External links

https://access.redhat.com/errata/RHSA-2020:2839

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.