Bug 1551818 (CVE-2017-1002102)

Summary: CVE-2017-1002102 kubernetes: Malicious containers can delete any file from the node
Product: [Other] Security Response Reporter: Jason Shepherd <jshepherd>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: admiller, bleanhar, ccoleman, dedgar, dmcphers, eparis, hchiramm, ichavero, jbrooks, jcajka, jchaloup, jgoulding, jkeck, madam, nhorman, rhs-bugs, security-response-team, sisharma, ssaha, storage-qa-internal, tdawson, tstclair, vbatts, vbellur
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: If docs needed, set a value
Doc Text:
This vulnerability allows containers using a secret, configMap, projected, or downwardAPI volume to trigger deletion of arbitrary files and directories on the nodes where they are running. An attacker could use this flaw to delete arbitrary file or directories on node host.
 Story Points: ---
Clone Of: Environment:
Last Closed: 2019-07-12 13:05:07 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: 1536576, 1553541, 1554168, 1554169, 1554170, 1554171, 1554539, 1554573    
Bug Blocks: 1536902    

Description Jason Shepherd 2018-03-06 00:29:27 UTC 
A symlink race in the openShift node process allows a malicious container to trick the node into deleting any file.

Every sync iteration, the atomic writer code walks the volume looking for files that shouldn't be there or files that have changed.  When it finds files that shouldn't be there, it adds them to a list. Once it's finished walking the tree, it sorts the list lexicographically then starts at the end (to make sure that files are removed before the directories that contain them) and removes them one by one.

Because (a) the volume isn't mounted read-only by the runtime and (b) there is a time between finding the file and deleting the file, a malicious container can set up conditions to win a race such that the file to be deleted is removed and replaced with a symlink (to a node file to be deleted) between the time that the kubelet finds the file and the time it deletes it.
Comment 1 Jason Shepherd 2018-03-06 00:32:37 UTC 
Acknowledgments:

Name: Joel Smith (Red Hat)
Comment 4 errata-xmlrpc 2018-03-12 19:38:43 UTC 
This issue has been addressed in the following products:

  Red Hat OpenShift Container Platform 3.3
  Red Hat OpenShift Container Platform 3.4
  Red Hat OpenShift Container Platform 3.5
  Red Hat OpenShift Container Platform 3.6
  Red Hat OpenShift Container Platform 3.7

Via RHSA-2018:0475 https://access.redhat.com/errata/RHSA-2018:0475
Comment 5 Jason Shepherd 2018-03-12 22:39:32 UTC 
Created kubernetes tracking bugs for this issue:

Affects: fedora-all [bug 1554539]
Comment 6 Jason Shepherd 2018-03-13 00:21:09 UTC 
Created origin tracking bugs for this issue:

Affects: fedora-all [bug 1554573]
Comment 7 Product Security DevOps Team 2019-07-12 13:05:07 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-2017-1002102