Path traversal and file disclosure vulnerability in Apache HTTP Server 2.4.49

CVE-2021-41773
7.5HIGH

Key Information

Vendor
Apache
Status
Apache Http Server
Vendor
CVE Published:
5 October 2021

Badges

👾 Exploit Exists🔴 Public PoC🟣 EPSS 97%

Summary

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.

CISA Reported

CISA provides regional cyber and physical services to support security and resilience across the United States. CISA monitor the most dangerious vulnerabilities and have identifed CVE-2021-41773 as being exploited and is known by the CISA as enabling ransomware campaigns.

The CISA's recommendation is: Apply updates per vendor instructions.

Affected Version(s)

Apache HTTP Server = Apache HTTP Server 2.4 2.4.49

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

EPSS Score

97% chance of being exploited in the next 30 days.

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
High
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • 👾

    Exploit exists.

  • Vulnerability published.

  • fixed by r1893775 in 2.4.50

  • reported

  • Vulnerability Reserved.

Collectors

NVD DatabaseMitre DatabaseCISA Database111 Proof of Concept(s)

Credit

This issue was reported by Ash Daulton along with the cPanel Security Team
.