Fedora 34 update for httpd



Risk Critical
Patch available YES
Number of vulnerabilities 4
CVE-ID CVE-2021-41524
CVE-2021-33193
CVE-2021-41773
CVE-2021-42013
CWE-ID CWE-476
CWE-444
CWE-22
CWE-78
Exploitation vector Network
Public exploit Vulnerability #3 is being exploited in the wild.
Vulnerability #4 is being exploited in the wild.
Vulnerable software
 Fedora
Operating systems & Components / Operating system

httpd
Operating systems & Components / Operating system package or component

Vendor Fedoraproject

Security Bulletin

This security bulletin contains information about 4 vulnerabilities.

1) NULL pointer dereference

EUVDB-ID: #VU57062

Risk: Medium

CVSSv4.0: 6.6 [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:U/U:Green]

CVE-ID: CVE-2021-41524

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 when processing HTTP/2 requests. A remote attacker can send a specially crafted HTTP/2 request to the affected Apache HTTP server and perform a denial of service (DoS) attack.

Mitigation

Install updates from vendor's repository.

Vulnerable software versions

Fedora: 34

httpd: before 2.4.50-1.fc34

CPE2.3 External links

https://bodhi.fedoraproject.org/updates/FEDORA-2021-5d2d4b6ac5


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) Inconsistent interpretation of HTTP requests

EUVDB-ID: #VU56474

Risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-33193

CWE-ID: CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling')

Exploit availability: No

Description

The vulnerability allows a remote attacker to preform HTTP/2 request smuggling attacks.

The vulnerability exists due to improper validation of HTTP/2 requests in mod_proxy in Apache HTTP Server. A remote attacker can send a specially crafted HTTP/2 request to the server and smuggle arbitrary HTTP headers.

Successful exploitation of vulnerability may allow an attacker to poison web server cache and perform phishing attacks.

Mitigation

Install updates from vendor's repository.

Vulnerable software versions

Fedora: 34

httpd: before 2.4.50-1.fc34

CPE2.3 External links

https://bodhi.fedoraproject.org/updates/FEDORA-2021-5d2d4b6ac5


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.

3) Path traversal

EUVDB-ID: #VU57063

Risk: Critical

CVSSv4.0: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Red]

CVE-ID: CVE-2021-41773

CWE-ID: CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to perform directory traversal attacks.

The vulnerability exists due to input validation error when processing directory traversal sequences. A remote attacker can send a specially crafted HTTP request to map URLs to files outside the expected document root. If files outside of the document root are not protected by "require all denied" these requests can succeed. Additionally this flaw could leak the source of interpreted files like CGI scripts.

The vulnerability can be used to execute arbitrary OS commands on the system.

Note, the vulnerability is being actively exploited in the wild.

Mitigation

Install updates from vendor's repository.

Vulnerable software versions

Fedora: 34

httpd: before 2.4.50-1.fc34

CPE2.3 External links

https://bodhi.fedoraproject.org/updates/FEDORA-2021-5d2d4b6ac5


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?

Yes. This vulnerability is being exploited in the wild.

4) OS Command Injection

EUVDB-ID: #VU57127

Risk: Critical

CVSSv4.0: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Red]

CVE-ID: CVE-2021-42013

CWE-ID: CWE-78 - Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

Exploit availability: Yes

Description

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

The vulnerability exists due to insufficient fix for the path traversal vulnerability #VU57063 (CVE-2021-41733). A remote unauthenticated attacker can send a specially crafted HTTP request to the affected server and execute arbitrary OS commands on the target system.

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

Mitigation

Install updates from vendor's repository.

Vulnerable software versions

Fedora: 34

httpd: before 2.4.50-1.fc34

CPE2.3 External links

https://bodhi.fedoraproject.org/updates/FEDORA-2021-5d2d4b6ac5


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?

Yes. This vulnerability is being exploited in the wild.



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