VulnerabilityAnalyzed

CVE-2021-42013

Apache HTTP Server Path Traversal Vulnerability

KEVCRITICAL 9.8EPSS 100.0%

Does this matter?

Known to be exploited in the wild (CISA KEV, CISA remediation deadline 17 November 2021). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.

Description

It was found that the fix for CVE-2021-41773 in Apache HTTP Server 2.4.50 was insufficient. An attacker could use a path traversal attack to map URLs to files outside the directories configured by Alias-like directives. If files outside of these directories are not protected by the usual default configuration "require all denied", these requests can succeed. If CGI scripts are also enabled for these aliased pathes, this could allow for remote code execution. This issue only affects Apache 2.4.49 and Apache 2.4.50 and not earlier versions.

CVSS 3.1: 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS: 99.96% probability · 100th percentile
CISA KEV: Listed 3 November 2021 · due 17 November 2021 · used in ransomware campaigns
Weakness: CWE-22
Affected: apache/http server · fedoraproject/fedora · oracle/instantis enterprisetrack · oracle/jd edwards enterpriseone tools · oracle/secure backup · netapp/cloud backup
Source: security@apache.org

CISA notes

Apply updates per vendor instructions. https://nvd.nist.gov/vuln/detail/CVE-2021-42013

References

http://jvn.jp/en/jp/JVN51106450/index.htmlThird Party Advisory
http://packetstormsecurity.com/files/164501/Apache-HTTP-Server-2.4.50-Path-Traversal-Code-Execution.htmlExploit, Third Party Advisory, VDB Entry
http://packetstormsecurity.com/files/164609/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.htmlExploit, Third Party Advisory, VDB Entry
http://packetstormsecurity.com/files/164629/Apache-2.4.49-2.4.50-Traversal-Remote-Code-Execution.htmlExploit, Third Party Advisory, VDB Entry
http://packetstormsecurity.com/files/164941/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.htmlExploit, Third Party Advisory, VDB Entry
http://packetstormsecurity.com/files/165089/Apache-HTTP-Server-2.4.50-CVE-2021-42013-Exploitation.htmlThird Party Advisory, VDB Entry
http://packetstormsecurity.com/files/167397/Apache-2.4.50-Remote-Code-Execution.htmlExploit, Third Party Advisory, VDB Entry
http://www.openwall.com/lists/oss-security/2021/10/07/6Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/10/08/1Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/10/08/2Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/10/08/3Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/10/08/4Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/10/08/5Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/10/08/6Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/10/09/1Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/10/11/4Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/10/15/3Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/10/16/1Mailing List, Third Party Advisory
https://httpd.apache.org/security/vulnerabilities_24.htmlRelease Notes, Vendor Advisory
https://lists.apache.org/thread.html/r17a4c6ce9aff662efd9459e9d1850ab4a611cb23392fc68264c72cb3%40%3Ccvs.httpd.apache.org%3EMailing List, Patch
https://lists.apache.org/thread.html/r7c795cd45a3384d4d27e57618a215b0ed19cb6ca8eb070061ad5d837%40%3Cannounce.apache.org%3EMailing List
https://lists.apache.org/thread.html/rb5b0e46f179f60b0c70204656bc52fcb558e961cb4d06a971e9e3efb%40%3Cusers.httpd.apache.org%3EMailing List
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RMIIEFINL6FUIOPD2A3M5XC6DH45Y3CC/Release Notes
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WS5RVHOIIRECG65ZBTZY7IEJVWQSQPG3/Release Notes
https://security.gentoo.org/glsa/202208-20Third Party Advisory
https://security.netapp.com/advisory/ntap-20211029-0009/Third Party Advisory
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-pathtrv-LAzg68cZThird Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.htmlPatch, Third Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.htmlPatch, Third Party Advisory
https://www.povilaika.com/apache-2-4-50-exploit/Exploit, Third Party Advisory

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.