Bug 1216497

Summary:	VUL-0: squid: Denial of Service in Gopher gateway
Product:	[Novell Products] SUSE Security Incidents	Reporter:	Alexander Bergmann <abergmann>
Component:	Incidents	Assignee:	Security Team bot <security-team>
Status:	RESOLVED DUPLICATE	QA Contact:	Security Team bot <security-team>
Severity:	Normal
Priority:	P3 - Medium	CC:	abergmann, amajer, stoyan.manolov, thomas.leroy
Version:	unspecified
Target Milestone:	---
Hardware:	Other
OS:	Other
URL:	https://smash.suse.de/issue/382742/
Whiteboard:
Found By:	---	Services Priority:
Business Priority:		Blocker:	---
Marketing QA Status:	---	IT Deployment:	---

Description Alexander Bergmann 2023-10-23 11:52:49 UTC

https://github.com/squid-cache/squid/security/advisories/GHSA-cg5h-v6vc-w33f

Package: Squid (Squid)
Affected versions: <6.0.1
Patched versions: 6.0.1

Description:
Due to a NULL pointer dereference bug Squid is vulnerable to a Denial of Service attack against Squid's Gopher gateway.

Severity:
The gopher protocol is always available and enabled in Squid prior to Squid 6.0.1

Responses triggering this bug are possible to be received from any gopher server, even those without malicious intent.

CVSS Score of 7.5
https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H&version=3.1

Updated Packages:
The gopher support has been removed in Squid version 6.0.1

If you are using a prepackaged version of Squid then please refer
to the package vendor for availability information on updated
packages.

Determining if your version is vulnerable:
All Squid-2.x up to and including 2.7.STABLE9 are vulnerable.
All Squid-3.x up to and including 3.5.28 are vulnerable.
All Squid-4.x up to and including 4.16 are vulnerable.
All Squid-5.x up to and including 5.9 are vulnerable.

Comment 1 Thomas Leroy 2023-10-24 13:58:11 UTC

All codestreams are vulnerable, no fix available, but there could be an easy workaround by rejecting gopher URL request, by adding the following to the squid.conf file:

```
acl gopher proto gopher
http_access deny gopher
```

Comment 2 Alexander Bergmann 2023-10-26 12:13:29 UTC

I've double checked the gopher functionality inside my test setup. Additionally to the 2 lines above it was necessary to disable the gopher port 70 entry by removing the following line:

acl Safe_ports port 70          # gopher


To clarify this, I've opened a bug report with squid up-stream:
https://bugs.squid-cache.org/show_bug.cgi?id=5310

Comment 3 Alexander Bergmann 2023-10-30 12:46:56 UTC

Workaround:

Please make sure that the following lines are placed before all  "http_access allow" rules, otherwise the restriction will not work:

```
acl gopher proto gopher
http_access deny gopher
```

Comment 6 Thomas Leroy 2023-11-20 09:56:30 UTC

Duplicate

*** This bug has been marked as a duplicate of bug 1216926 ***