Bug 1952674 (CVE-2021-29136) - CVE-2021-29136 singularity: allows overwriting of host files
Summary: CVE-2021-29136 singularity: allows overwriting of host files
Keywords:
Status: CLOSED UPSTREAM
Alias: CVE-2021-29136
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 1946970 1952675 1952676
Blocks:
TreeView+ depends on / blocked
 
Reported: 2021-04-22 20:19 UTC by Guilherme de Almeida Suckevicz
Modified: 2021-04-22 22:46 UTC (History)
3 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2021-04-22 22:46:33 UTC
Embargoed:

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Description Guilherme de Almeida Suckevicz 2021-04-22 20:19:55 UTC 
This vulnerability is in umoci but it was found that singularity is also affected.

A dependency used by Singularity to extract docker/OCI image layers can be tricked into modifying host files by creating a malicious layer that has a symlink with the name "." (or "/"), when running as root. This vulnerability affects a singularity build or singularity pull as root, from a docker or OCI source, as well as the implicit build to SIF that occurs through root use of run/exec/shell against a malicious docker/OCI image URI.

Reference:
https://github.com/hpcng/singularity/releases
Comment 1 Guilherme de Almeida Suckevicz 2021-04-22 20:20:21 UTC 
Created singularity tracking bugs for this issue:

Affects: epel-all [bug 1952676]
Affects: fedora-all [bug 1952675]
Comment 2 Dave Dykstra 2021-04-22 21:56:06 UTC 
This is being addressed in #1946970
Comment 3 Product Security DevOps Team 2021-04-22 22:46:33 UTC 
This CVE Bugzilla entry is for community support informational purposes only as it does not affect a package in a commercially supported Red Hat product. Refer to the dependent bugs for status of those individual community products.
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