Backdoor.PHP.DEFACER.B
Windows, Linux, Mac
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 executes commands from a remote malicious user, effectively compromising the affected system.
TECHNICAL DETAILS
10,744 bytes
PHP
No
01 Feb 2022
Connects to URLs/IPs, Downloads files
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.
Installation
This Backdoor adds the following folders:
- If request parameter "getTools" is set and directory "/home/{username}/.cpanel" exists
- /home/{username}/mail/{server name}/smtpfox-{random}
- /home/{username}/mail/{server name}/smtpfox-{random}/.Archive
- /home/{username}/mail/{server name}/smtpfox-{random}/.Drafts
- /home/{username}/mail/{server name}/smtpfox-{random}/.Sent
- /home/{username}/mail/{server name}/smtpfox-{random}/.spam
- /home/{username}/mail/{server name}/smtpfox-{random}/.Trash
- /home/{username}/mail/{server name}/smtpfox-{random}/cur
- /home/{username}/mail/{server name}/smtpfox-{random}/new
- /home/{username}/mail/{server name}/smtpfox-{random}/tmp
It drops the following files:
- If request parameter "getTools" is set and directory "/home/{username}/.cpanel" exists
- /home/{username}/mail/{server name}/smtpfox-{random}/dovecot-acl-list
- /home/{username}/mail/{server name}/smtpfox-{random}/dovecot-uidlist
- /home/{username}/mail/{server name}/smtpfox-{random}/dovecot-uidvalidity
- /home/{username}/mail/{server name}/smtpfox-{random}/dovecot-uidvalidity.5e196afc
- /home/{username}/mail/{server name}/smtpfox-{random}/dovecot.index.log
- /home/{username}/mail/{server name}/smtpfox-{random}/dovecot.list.index.log
- /home/{username}/mail/{server name}/smtpfox-{random}/dovecot.mailbox.log
- /home/{username}/mail/{server name}/smtpfox-{random}/maildirsize
- /home/{username}/mail/{server name}/smtpfox-{random}/subscriptions
- If request parameter "getTools" is set and directory "{document root dir}/wp-admin" exists:
- {Document Root Directory}/wp-admin/php.ini
- {Document Root Directory}/wp-includes/php.ini
- {Document Root Directory}/wp-content/php.ini
- {Document Root Directory}/wp-admin/.htaccess
- {Document Root Directory}/wp-includes/.htaccess
- {Document Root Directory}/wp-content/.htaccess
- {Document Root Directory}/wp-includes/index.php
- Else If directory "{document root dir}/components" exists:
- {Document Root Directory}/components/php.ini
- {Document Root Directory}/administrator/php.ini
- {Document Root Directory}/libraries/php.ini
- {Document Root Directory}/components/.htaccess
- {Document Root Directory}/administrator/.htaccess
- {Document Root Directory}/libraries/.htaccess
- Else:
- {Document Root Directory}/php.ini
It takes advantage of the following vulnerability/vulnerabilities to elevate privileges:
- “Reset Password for cPanel accounts” feature
- Through replacing the contact email with an attacker defined email address and resetting the account password
Other System Modifications
This Backdoor modifies the following file(s):
- It rewrites the following cPanel files' email address:
- /home/{username}/.contactemail
- /home/{username}/.cpanel/contactinfo
- It appends created SMTP credentials:
- /home/{username}/etc/{server name}/shadow
- /home/{username}/etc/shadow
Backdoor Routine
This Backdoor executes the following commands from a remote malicious user:
- Replace cPanel email address
- Reset cPanel Password
- Download and drop tools
- Create email account
Download Routine
This Backdoor downloads the file from the following URL and renames the file when stored in the affected system:
- http://{BLOCKED}ousfox.to/files/olux-shell.txt
- http://{BLOCKED}ousfox.to/files/xleet-shell.txt
- http://{BLOCKED}ousfox.to/files/mailer.txt
It saves the files it downloads using the following names:
- If directory "{document root dir}/wp-admin" exists:
- {Document Root Directory}/wp-admin/{random string}.php
- {Document Root Directory}/wp-includes/{random string}.php
- {Document Root Directory}/wp-content/{random string}.php
- Else If directory "{document root dir}/components" exists:
- {Document Root Directory}/components/{random}.php
- {Document Root Directory}/administrator/{random}.php
- {Document Root Directory}/libraries/{random}.php
- Else:
- {Document Root Directory}/{random string}.php
- {Document Root Directory}/{random string}.php
- {Document Root Directory}/{random string}.php
Other Details
This Backdoor requires being hosted on a web server in order to proceed with its intended routine.
NOTES:
This Backdoor does the following:
- It attempts to access folloing URL to login cPanel with created credentials:
- https://localhost:2087/login/
- It connects to the following URLs to reset cPanel password:
- https://localhost:2083/resetpass
- http://localhost:2082/resetpass
- It receives an attacker defined email address passed through request parameter "email"
- It proceeds to download and dropping routine if request parameter "getTools" is set
- It changes cPanel password to "f0x#{random}#x" if request parameter "code" is set
- It changes cPanel email addresses to one of the following depending on the request parameter set:
- {value of ?email= request parameter}
- smtpfox-{random}@{server name}
SOLUTION
9.800
17.352.08
01 Feb 2022
17.353.00
02 Feb 2022
Step 1
Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.
Step 2
Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.
Step 3
Search and delete this file
- {Document Root Directory}/wp-admin/{random string}.php
- {Document Root Directory}/wp-includes/{random string}.php
- {Document Root Directory}/wp-content/{random string}.php
- {Document Root Directory}/components/{random}.php
- {Document Root Directory}/administrator/{random}.php
- {Document Root Directory}/libraries/{random}.php
- {Document Root Directory}/{random string}.php
- {Document Root Directory}/{random string}.php
- {Document Root Directory}/{random string}.php
- {Document Root Directory}/wp-admin/php.ini
- {Document Root Directory}/wp-includes/php.ini
- {Document Root Directory}/wp-content/php.ini
- {Document Root Directory}/wp-admin/.htaccess
- {Document Root Directory}/wp-includes/.htaccess
- {Document Root Directory}/wp-content/.htaccess
- {Document Root Directory}/wp-includes/index.php
- {Document Root Directory}/components/php.ini
- {Document Root Directory}/administrator/php.ini
- {Document Root Directory}/libraries/php.ini
- {Document Root Directory}/components/.htaccess
- {Document Root Directory}/administrator/.htaccess
- {Document Root Directory}/libraries/.htaccess
- {Document Root Directory}/php.ini
- /home/{username}/mail/{server name}/smtpfox-{random}/dovecot-acl-list
- /home/{username}/mail/{server name}/smtpfox-{random}/dovecot-uidlist
- /home/{username}/mail/{server name}/smtpfox-{random}/dovecot-uidvalidity
- /home/{username}/mail/{server name}/smtpfox-{random}/dovecot-uidvalidity.5e196afc
- /home/{username}/mail/{server name}/smtpfox-{random}/dovecot.index.log
- /home/{username}/mail/{server name}/smtpfox-{random}/dovecot.list.index.log
- /home/{username}/mail/{server name}/smtpfox-{random}/dovecot.mailbox.log
- /home/{username}/mail/{server name}/smtpfox-{random}/maildirsize
- /home/{username}/mail/{server name}/smtpfox-{random}/subscriptions
Step 4
Search and delete this folder
- /home/{username}/mail/{server name}/smtpfox-{random}
- /home/{username}/mail/{server name}/smtpfox-{random}/.Archive
- /home/{username}/mail/{server name}/smtpfox-{random}/.Drafts
- /home/{username}/mail/{server name}/smtpfox-{random}/.Sent
- /home/{username}/mail/{server name}/smtpfox-{random}/.spam
- /home/{username}/mail/{server name}/smtpfox-{random}/.Trash
- /home/{username}/mail/{server name}/smtpfox-{random}/cur
- /home/{username}/mail/{server name}/smtpfox-{random}/new
- /home/{username}/mail/{server name}/smtpfox-{random}/tmp
Step 5
Scan your computer with your Trend Micro product to delete files detected as Backdoor.PHP.DEFACER.B. 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 the following Trend Micro Support pages for more information:
Step 6
Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.
- /home/{username}/.contactemail
- /home/{username}/.cpanel/contactinfo
- /home/{username}/etc/{server name}/shadow
- /home/{username}/etc/shadow
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