Bug 2016640 (CVE-2020-27304)

Summary:	CVE-2020-27304 civetweb: directory traversal when using the built-in example HTTP form-based file upload mechanism via the mg_handle_form_request API
Product:	[Other] Security Response	Reporter:	Guilherme de Almeida Suckevicz <gsuckevi>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	amctagga, anharris, bniver, flucifre, gmeno, hvyas, mbenjamin, mhackett, osoukup, sfowler, sostapov, vereddy
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	CivetWeb 1.15	Doc Type:	If docs needed, set a value
Doc Text:	A remote code execution vulnerability was found in CivetWeb (embeddable web server/library). Due to a directory traversal issue, an attacker is able to add or overwrite files that are subsequently executed which lead to impact to confidentiality, integrity, and availability of the application.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-12-01 17:52:04 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2020730, 2020740
Bug Blocks:	2016641

Description Guilherme de Almeida Suckevicz 2021-10-22 13:33:02 UTC

The CivetWeb web library does not validate uploaded filepaths when running on an OS other than Windows, when using the built-in HTTP form-based file upload mechanism, via the mg_handle_form_request API. Web applications that use the file upload form handler, and use parts of the user-controlled filename in the output path, are susceptible to directory traversal

Reference:
https://groups.google.com/g/civetweb/c/yPBxNXdGgJQ
https://jfrog.com/blog/cve-2020-27304-rce-via-directory-traversal-in-civetweb-http-server/

Comment 1 Przemyslaw Roguski 2021-11-02 16:14:20 UTC

Important to mention that this vulnerability does not affect component if at least one of these is true:
- You are using the pre-built Windows executable from SourceForge or GitHub releases (no CivetWeb version is affected)
- You are using "make" (for Linux) or "cmake" in the civetweb root directory to build the server on your own.
- You are building only using files from src/ and include/ but not examples/.
- You do not have html form handlers, that allow file upload.

Comment 2 Przemyslaw Roguski 2021-11-02 16:21:26 UTC

Upstream fix:
https://github.com/civetweb/civetweb/commit/b2ed60c589172b37f3d705c69d84313eeb8348b1

Comment 4 errata-xmlrpc 2021-12-01 17:24:15 UTC

This issue has been addressed in the following products:

  RHACS-3.67-RHEL-8

Via RHSA-2021:4902 https://access.redhat.com/errata/RHSA-2021:4902

Comment 5 Product Security DevOps Team 2021-12-01 17:52:02 UTC

This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2020-27304