CVE-2021-41773

05.10.2021, 09:15

A flaw was found in a change made to path normalization in Apache HTTP Server 2.4.49. 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 is known to be exploited in the wild. This issue only affects Apache 2.4.49 and not earlier versions. The fix in Apache HTTP Server 2.4.50 was found to be incomplete, see CVE-2021-42013.

Path Traversal

Provider	Type	Base Score	Atk. Vector	Atk. Complexity	Priv. Required	Vector
NIST	NIST	7.5 HIGH	NETWORK	LOW	NONE	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
apache	CNA	---				---
CVE	ADP	---				---
CISA-ADP	ADP	7.5 HIGH	NETWORK	LOW	NONE	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Base Score

CVSS 3.x

EPSS Score

Percentile: 99%

Vendor	Product	Version
apache	http_server	2.4.49
oracle	instantis_enterprisetrack	17.1
oracle	instantis_enterprisetrack	17.2
oracle	instantis_enterprisetrack	17.3
netapp	cloud_backup	-

𝑥

= Vulnerable software versions

Debian Releases

Debian Product

Codename

apache2

bullseye	2.4.62-1~deb11u1 not-affected
buster	not-affected
stretch	not-affected
bullseye (security)	2.4.62-1~deb11u2 fixed
bookworm	2.4.62-1~deb12u1 fixed
bookworm (security)	2.4.62-1~deb12u2 fixed
sid	2.4.62-3 fixed
trixie	2.4.62-3 fixed

Ubuntu Releases

Ubuntu Product

Codename

apache2

jammy	not-affected
impish	not-affected
hirsute	not-affected
focal	not-affected
bionic	not-affected
xenial	not-affected
trusty	not-affected

Known Exploits!

Common Weakness Enumeration

CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
The software uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the software does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

References

http://packetstormsecurity.com/files/164418/Apache-HTTP-Server-2.4.49-Path-Traversal-Remote-Code-Execution.html

http://packetstormsecurity.com/files/164418/Apache-HTTP-Server-2.4.49-Path-Traversal.html

http://packetstormsecurity.com/files/164629/Apache-2.4.49-2.4.50-Traversal-Remote-Code-Execution.html

http://packetstormsecurity.com/files/164941/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.html

http://www.openwall.com/lists/oss-security/2021/10/05/2

http://www.openwall.com/lists/oss-security/2021/10/07/1

http://www.openwall.com/lists/oss-security/2021/10/07/6

http://www.openwall.com/lists/oss-security/2021/10/08/1

http://www.openwall.com/lists/oss-security/2021/10/08/2

http://www.openwall.com/lists/oss-security/2021/10/08/3

http://www.openwall.com/lists/oss-security/2021/10/08/4

http://www.openwall.com/lists/oss-security/2021/10/08/5

http://www.openwall.com/lists/oss-security/2021/10/08/6

http://www.openwall.com/lists/oss-security/2021/10/09/1

http://www.openwall.com/lists/oss-security/2021/10/11/4

http://www.openwall.com/lists/oss-security/2021/10/15/3

http://www.openwall.com/lists/oss-security/2021/10/16/1

https://httpd.apache.org/security/vulnerabilities_24.html

https://lists.apache.org/thread.html/r17a4c6ce9aff662efd9459e9d1850ab4a611cb23392fc68264c72cb3%40%3Ccvs.httpd.apache.org%3E

https://lists.apache.org/thread.html/r6abf5f2ba6f1aa8b1030f95367aaf17660c4e4c78cb2338aee18982f%40%3Cusers.httpd.apache.org%3E

https://lists.apache.org/thread.html/r7c795cd45a3384d4d27e57618a215b0ed19cb6ca8eb070061ad5d837%40%3Cannounce.apache.org%3E

https://lists.apache.org/thread.html/r98d704ed4377ed889d40479db79ed1ee2f43b2ebdd79ce84b042df45%40%3Cannounce.apache.org%3E

https://lists.apache.org/thread.html/rb5b0e46f179f60b0c70204656bc52fcb558e961cb4d06a971e9e3efb%40%3Cusers.httpd.apache.org%3E

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RMIIEFINL6FUIOPD2A3M5XC6DH45Y3CC/

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WS5RVHOIIRECG65ZBTZY7IEJVWQSQPG3/

https://security.gentoo.org/glsa/202208-20

https://security.netapp.com/advisory/ntap-20211029-0009/

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-pathtrv-LAzg68cZ

https://www.oracle.com/security-alerts/cpujan2022.html

http://packetstormsecurity.com/files/164418/Apache-HTTP-Server-2.4.49-Path-Traversal-Remote-Code-Execution.html

http://packetstormsecurity.com/files/164418/Apache-HTTP-Server-2.4.49-Path-Traversal.html

http://packetstormsecurity.com/files/164629/Apache-2.4.49-2.4.50-Traversal-Remote-Code-Execution.html

http://packetstormsecurity.com/files/164941/Apache-HTTP-Server-2.4.50-Remote-Code-Execution.html

http://www.openwall.com/lists/oss-security/2021/10/05/2

http://www.openwall.com/lists/oss-security/2021/10/07/1

http://www.openwall.com/lists/oss-security/2021/10/07/6

http://www.openwall.com/lists/oss-security/2021/10/08/1

http://www.openwall.com/lists/oss-security/2021/10/08/2

http://www.openwall.com/lists/oss-security/2021/10/08/3

http://www.openwall.com/lists/oss-security/2021/10/08/4

http://www.openwall.com/lists/oss-security/2021/10/08/5

http://www.openwall.com/lists/oss-security/2021/10/08/6

http://www.openwall.com/lists/oss-security/2021/10/09/1

http://www.openwall.com/lists/oss-security/2021/10/11/4

http://www.openwall.com/lists/oss-security/2021/10/15/3

http://www.openwall.com/lists/oss-security/2021/10/16/1

https://httpd.apache.org/security/vulnerabilities_24.html

https://lists.apache.org/thread.html/r17a4c6ce9aff662efd9459e9d1850ab4a611cb23392fc68264c72cb3%40%3Ccvs.httpd.apache.org%3E

https://lists.apache.org/thread.html/r6abf5f2ba6f1aa8b1030f95367aaf17660c4e4c78cb2338aee18982f%40%3Cusers.httpd.apache.org%3E

https://lists.apache.org/thread.html/r7c795cd45a3384d4d27e57618a215b0ed19cb6ca8eb070061ad5d837%40%3Cannounce.apache.org%3E

https://lists.apache.org/thread.html/r98d704ed4377ed889d40479db79ed1ee2f43b2ebdd79ce84b042df45%40%3Cannounce.apache.org%3E

https://lists.apache.org/thread.html/rb5b0e46f179f60b0c70204656bc52fcb558e961cb4d06a971e9e3efb%40%3Cusers.httpd.apache.org%3E

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RMIIEFINL6FUIOPD2A3M5XC6DH45Y3CC/

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WS5RVHOIIRECG65ZBTZY7IEJVWQSQPG3/

https://security.gentoo.org/glsa/202208-20

https://security.netapp.com/advisory/ntap-20211029-0009/

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-pathtrv-LAzg68cZ

https://www.oracle.com/security-alerts/cpujan2022.html