Bug 1607283 (CVE-2018-4182) - CVE-2018-4182 cups: Sandbox bypass due to insecure error handling
Summary: CVE-2018-4182 cups: Sandbox bypass due to insecure error handling
Keywords:
Status: CLOSED NOTABUG
Alias: CVE-2018-4182
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 1607293 1607295
Blocks: 1607292
TreeView+ depends on / blocked
 
Reported: 2018-07-23 08:08 UTC by Andrej Nemec
Modified: 2019-09-29 14:45 UTC (History)
12 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
A Sandbox bypass has been discovered in cups on macOS due to insecure error handling. An attacker that has obtained sandboxed root access can use this flow to escape the sandbox.
Clone Of:
Environment:
Last Closed: 2018-07-25 09:18:58 UTC


Attachments (Terms of Use)

Description Andrej Nemec 2018-07-23 08:08:50 UTC
It is possible to cause cups-exec to execute backends without a sandbox profile by causing cupsdCreateProfile() to fail.  An attacker that has obtained sandboxed root access can accomplish this by setting the CUPS temporary directory to immutable using chflags, which will prevent the profile from being written to disk.

References:

https://blog.gdssecurity.com/labs/2018/7/11/cups-local-privilege-escalation-and-sandbox-escapes.html

Upstream patch:

https://github.com/apple/cups/commit/d47f6aec436e0e9df6554436e391471097686ecc

Comment 1 Andrej Nemec 2018-07-23 08:31:41 UTC
Created cups tracking bugs for this issue:

Affects: fedora-all [bug 1607293]

Comment 3 Riccardo Schirone 2018-07-25 09:16:40 UTC
Fedora and RHEL are not affected by this flaw since Sandbox feature is not enabled on Linux.

Comment 4 Riccardo Schirone 2018-08-28 13:00:24 UTC
Statement:

This issue did not affect the versions of cups as shipped with Red Hat Enterprise Linux as cups on Linux does not support the Sandbox feature.


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