Red Hat Enterprise Linux 8 update for the httpd:2.4 module



Published: 2021-10-13 | Updated: 2021-10-18
Risk High
Patch available YES
Number of vulnerabilities 2
CVE-ID CVE-2021-26691
CVE-2021-40438
CWE-ID CWE-476
CWE-918
Exploitation vector Network
Public exploit Public exploit code for vulnerability #2 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 Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) NULL pointer dereference

EUVDB-ID: #VU53776

Risk: Low

CVSSv3.1: 5.2 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-26691

CWE-ID: CWE-476 - NULL Pointer Dereference

Exploit availability: No

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 in mod_session. A a malicious backend server or SessionHeader can trigger a denial of service (DoS) condition.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

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

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

Red Hat Enterprise Linux Server - TUS: 8.4

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

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

Red Hat Enterprise Linux Server - AUS: 8.4

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

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

CPE2.3 External links

http://access.redhat.com/errata/RHSA-2021:3816

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.

2) Server-Side Request Forgery (SSRF)

EUVDB-ID: #VU56678

Risk: High

CVSSv3.1: 8.4 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N/E:P/RL:O/RC:C]

CVE-ID: CVE-2021-40438

CWE-ID: CWE-918 - Server-Side Request Forgery (SSRF)

Exploit availability: Yes

Description

The disclosed vulnerability allows a remote attacker to perform SSRF attacks.

The vulnerability exists due to insufficient validation of user-supplied input within the mod_proxy module in Apache HTTP Server. A remote attacker can send a specially crafted HTTP request with a chosen uri-path and trick the web server to initiate requests to arbitrary systems.

Successful exploitation of this vulnerability may allow a remote attacker gain access to sensitive data, located in the local network or send malicious requests to other servers from the vulnerable system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

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

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

Red Hat Enterprise Linux Server - TUS: 8.4

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

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

Red Hat Enterprise Linux Server - AUS: 8.4

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

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

CPE2.3 External links

http://access.redhat.com/errata/RHSA-2021:3816

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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