Red Hat Enterprise Linux 8 update for nginx-1.16.1-2.module



Published: 2021-06-09
Risk High
Patch available YES
Number of vulnerabilities 1
CVE ID CVE-2021-23017
CWE ID CWE-193
Exploitation vector Network
Public exploit Public exploit code for vulnerability #1 is available.
Vulnerable software
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Red Hat Enterprise Linux Server - Update Services for SAP Solutions
Operating systems & Components / Operating system package or component

Red Hat Enterprise Linux Server (for IBM Power LE) - Update Services for SAP Solutions
Operating systems & Components / Operating system package or component

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 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 x86_64 - Extended Update Support
Operating systems & Components / Operating system

Red Hat Enterprise Linux for ARM 64 - Extended Update Support
Operating systems & Components / Operating system

Red Hat Enterprise Linux for ARM 64
Operating systems & Components / Operating system

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

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

Red Hat Enterprise Linux for x86_64
Operating systems & Components / Operating system

Vendor Red Hat Inc.

Security Advisory

This security advisory describes one high risk vulnerability.

1) Off-by-one

Risk: High

CVSSv3.1: 7.3 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C] [PCI]

CVE-ID: CVE-2021-23017

CWE-ID: CWE-193 - Off-by-one Error

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to an off-by-one error within the ngx_resolver_copy() function when processing DNS responses. A remote attacker can trigger an off-by-one error, write a dot character (‘.’, 0x2E) out of bounds in a heap allocated buffer and execute arbitrary code on the system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

The vulnerability can be triggered by a DNS response in reply to a DNS request from nginx when the resolver primitive is configured. A specially crafted packet allows overwriting the least significant byte of next heap chunk metadata with 0x2E.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux Server - Update Services for SAP Solutions: 8.1, 8.4

Red Hat Enterprise Linux Server (for IBM Power LE) - Update Services for SAP Solutions: 8.1, 8.4

Red Hat Enterprise Linux Server - TUS: 8.2, 8.4

Red Hat Enterprise Linux for Power, little endian - Extended Update Support: 8.1, 8.4

Red Hat Enterprise Linux for IBM z Systems - Extended Update Support: 8.1, 8.4

Red Hat Enterprise Linux Server - AUS: 8.4

Red Hat Enterprise Linux for x86_64 - Extended Update Support: 8.1, 8.4

Red Hat Enterprise Linux for ARM 64 - Extended Update Support: 8.1, 8.4

Red Hat Enterprise Linux for ARM 64: 8

Red Hat Enterprise Linux for Power, little endian: 8

Red Hat Enterprise Linux for IBM z Systems: 8

Red Hat Enterprise Linux for x86_64: 8.0

CPE External links

https://access.redhat.com/errata/RHSA-2021:2290

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.



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