Internet Bug Bounty: important: Apache HTTP Server weakness in mod_rewrite when first segment of substitution matches filesystem path. (CVE-2024-38475)

2024-07-0306:58:50

orange

hackerone.com

$4920

internet bug bounty

apache http server

mod_rewrite

cve-2024-38475

security vulnerability

code execution

source code disclosure

unsafe rewriterules

unsafeprefixstat

CVSS3

9.1

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

NONE

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

AI Score

7.4

Confidence

High

JSON

I reported this vulnerability through the official Apache HTTP Server security email on April 1, 2024, and received a fix along with a CVE number on July 1, 2024. You can check detailed information from there:
> https://httpd.apache.org/security/vulnerabilities_24.html

Impact

Improper escaping of output in mod_rewrite in Apache HTTP Server 2.4.59 and earlier allows an attacker to map URLs to filesystem locations that are permitted to be served by the server but are not intentionally/directly reachable by any URL, resulting in code execution or source code disclosure.

Substitutions in server context that use a backreferences or variables as the first segment of the substitution are affected. Some unsafe RewiteRules will be broken by this change and the rewrite flag “UnsafePrefixStat” can be used to opt back in once ensuring the substitution is appropriately constrained.