PHP_WEBSHELL.SS
Windows
Threat Type: Backdoor
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
Downloaded from the Internet, Dropped by other malware
This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites. It may be hosted on a website and run when a user accesses the said website.
It connects to a website to send and receive information.
TECHNICAL DETAILS
15,521 bytes
Other
No
30 Oct 2015
Connects to URLs/IPs
Arrival Details
This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
It may be hosted on a website and run when a user accesses the said website.
Backdoor Routine
This backdoor connects to the following websites to send and receive information:
- {BLOCKED}38.com
- {BLOCKED}e8.com
- {BLOCKED}88.com
- {BLOCKED}cb.com
NOTES:
This backdoor is a PHP script injected in compromised web servers. It downloads data from its C&C and appends the downloaded code to itself.
It sends the following information:
- HTTP_USER_AGENT - user agent
- HTTP_REFERER - address of the page which referred the user agent to the current page
- REMOTE_ADDR - IP address from which the user is viewing the current page
- HTTP_HOST - contents of the host
- PHP_SELF - path of the currently executing script, relative to the document root
This backdoor does nothing if the user agent contains any of the following strings:
- ia_archiver
- msnbot
- rambler
- slurp
- yandex
SOLUTION
9.800
12.118.06
29 Oct 2015
12.119.00
30 Oct 2015
Step 1
Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.
Step 2
Scan your computer with your Trend Micro product to clean files detected as PHP_WEBSHELL.SS. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.
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