Vulnerability identifier: #VU46107

Vulnerability risk: Medium

CVSSv3.1: 6.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-11724

CWE-ID: CWE-444

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
OpenResty
Server applications / Web servers
lua-nginx-module
Web applications / Modules and components for CMS

Vendor: OpenResty Inc.

Description

The vulnerability allows a remote attacker to preform HTTP request smuggling attacks.

The vulnerability exists due to improper validation of HTTP requests in ngx_http_lua_subrequest.c in lua-nginx-module for OpenResy. A remote attacker can send a specially crafted HTTP request to the server and smuggle arbitrary HTTP headers.

Successful exploitation of vulnerability may allow an attacker to poison HTTP cache and perform phishing attacks.

Mitigation
Install update from vendor's website.

Vulnerable software versions

OpenResty: 1.15.8.1 - 1.15.8.3

lua-nginx-module: 0.10.0 rc0 - 0.10.16

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External links
http://github.com/openresty/lua-nginx-module/commit/9ab38e8ee35fc08a57636b1b6190dca70b0076fa
http://github.com/openresty/openresty/blob/4e8b4c395f842a078e429c80dd063b2323999957/patches/ngx_http_lua-0.10.15-fix_location_capture_content_length_chunked.patch
http://lists.debian.org/debian-lts-announce/2020/07/msg00014.html
http://www.debian.org/security/2020/dsa-4750

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.