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CVE-2021-40438: Apache HTTP Server-Side Request Forgery (SSRF)
CVE-2021-40438 is rated critical with a CVSS v3.1 base score of 9.0 and affects Apache Apache, along with 37 other products in NVD’s configuration data. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available. CISA added it to its Known Exploited Vulnerabilities catalog on 2021-12-01, which means exploitation in the wild has been observed.
Vulnerability description
A crafted request uri-path can cause mod_proxy to forward the request to an origin server choosen by the remote user. This issue affects Apache HTTP Server 2.4.48 and earlier.
Severity breakdown
CVSS v3.1 9.0: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
- Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
- Attack complexity: High. Success depends on conditions outside the attacker’s control.
- Privileges required: None. No account or prior access is needed.
- User interaction: None. No action from any user is needed.
- Scope: Changed. Impact reaches beyond the vulnerable component to other resources.
- Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
- Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
- Availability impact: High. Total loss of availability; the component can be shut down.
Underlying weakness
CWE-918: Server-Side Request Forgery
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
Affected products
- Apache HTTP Server: up to and including 2.4.48
- Oracle HTTP Server: 12.2.1.3.0; 12.2.1.4.0
- Resf Rocky Linux: 8.0
- Red Hat Enterprise Linux: 8.0
- Red Hat Enterprise Linux Eus: 8.1; 8.2; 8.4; 8.6; 8.8
- Red Hat Enterprise Linux For Arm 64: 8.0
- Red Hat Enterprise Linux For Arm 64 Eus: 8.6; 8.8
- Red Hat Enterprise Linux For IBM Z Systems: 7.0_s390x; 8.0
- Red Hat Enterprise Linux For IBM Z Systems Eus: 8.1; 8.4; 8.8
- Red Hat Enterprise Linux For IBM Z Systems Eus S390x: 8.2
- Red Hat Enterprise Linux For Power Big Endian: 7.0
- Red Hat Enterprise Linux For Power Little Endian: 7.0; 8.0
- Red Hat Enterprise Linux For Power Little Endian Eus: 8.1; 8.2; 8.4; 8.6; 8.8
- Red Hat Enterprise Linux For Scientific Computing: 7.0
- Red Hat Enterprise Linux Server: 7.0
References
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://httpd.apache.org/security/vulnerabilities_24.html
- https://cert-portal.siemens.com/productcert/pdf/ssa-685781.pdf
- https://lists.debian.org/debian-lts-announce/2021/10/msg00001.html
- https://security.gentoo.org/glsa/202208-20
- https://security.netapp.com/advisory/ntap-20211008-0004/
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-2.4.49-VWL69sWQ
- https://www.debian.org/security/2021/dsa-4982
- https://www.tenable.com/security/tns-2021-17
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SPBR6WUYBJNACHKE65SPL7TJOHX7RHWD/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNCYSR3BXT36FFF4XTCPL3HDQK4VP45R/
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-40438
- https://lists.apache.org/thread.html/r210807d0bb55f4aa6fbe1512be6bcc4dacd64e84940429fba329967a%40%3Cusers.httpd.apache.org%3E