Red Hat Enterprise Linux 7 update for zsh



Risk Low
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2019-20044
CWE-ID CWE-273
Exploitation vector Local
Public exploit Public exploit code for vulnerability #1 is available.
Vulnerable software
Red Hat Enterprise Linux EUS Compute Node
Operating systems & Components / Operating system

Red Hat Enterprise Linux for x86_64 - Extended Update Support
Operating systems & Components / Operating system

Red Hat Enterprise Linux Server - TUS
Operating systems & Components / Operating system

Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Operating systems & Components / Operating system

Red Hat Enterprise Linux for Power, little endian
Operating systems & Components / Operating system

Red Hat Enterprise Linux for Power, big endian - Extended Update Support
Operating systems & Components / Operating system

Red Hat Enterprise Linux for Power, big endian
Operating systems & Components / Operating system

Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Operating systems & Components / Operating system

Red Hat Enterprise Linux Server - AUS
Operating systems & Components / Operating system

Red Hat Enterprise Linux for IBM z Systems
Operating systems & Components / Operating system

Red Hat Enterprise Linux for Scientific Computing
Operating systems & Components / Operating system

Red Hat Enterprise Linux Desktop
Operating systems & Components / Operating system

Red Hat Enterprise Linux Workstation
Operating systems & Components / Operating system

Red Hat Enterprise Linux Server
Operating systems & Components / Operating system

zsh (Red Hat package)
Operating systems & Components / Operating system package or component

Vendor Red Hat Inc.

Security Bulletin

This security bulletin contains one low risk vulnerability.

1) Improper Check for Dropped Privileges

EUVDB-ID: #VU26210

Risk: Low

CVSSv4.0: 7.1 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Clear]

CVE-ID: CVE-2019-20044

CWE-ID: CWE-273 - Improper Check for Dropped Privileges

Exploit availability: Yes

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to Zsh fails to overwrite the saved uid, so the original privileges, dropped by the --no-PRIVILEGED option, can be restored by executing MODULE_PATH=/dir/with/module zmodload with a module that calls setuid(). A local user can execute arbitrary commands on the system with elevated privileges.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux EUS Compute Node: 7.7

Red Hat Enterprise Linux for x86_64 - Extended Update Support: 7.7

Red Hat Enterprise Linux Server - TUS: 7.7

Red Hat Enterprise Linux for Power, little endian - Extended Update Support: 7.7

Red Hat Enterprise Linux for Power, little endian: 7

Red Hat Enterprise Linux for Power, big endian - Extended Update Support: 7.7

Red Hat Enterprise Linux for Power, big endian: 7

Red Hat Enterprise Linux for IBM z Systems - Extended Update Support: 7.7

Red Hat Enterprise Linux Server - AUS: 7.7

Red Hat Enterprise Linux for IBM z Systems: 7

Red Hat Enterprise Linux for Scientific Computing: 7

Red Hat Enterprise Linux Desktop: 7

Red Hat Enterprise Linux Workstation: 7

Red Hat Enterprise Linux Server: 7

zsh (Red Hat package): before 5.0.2-34.el7_7.2

CPE2.3 External links

https://access.redhat.com/errata/RHSA-2020:0853


Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

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.



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