Backdoor.PHP.DOLLYWAY.A

April 15, 2021

Analysis by: Thea Patrice Tajonera

ALIASES:

N/A

PLATFORM:

Windows

OVERALL RISK RATING:

DAMAGE POTENTIAL:

DISTRIBUTION POTENTIAL:

REPORTED INFECTION:

INFORMATION EXPOSURE:

Threat Type: Backdoor
Destructiveness: No
Encrypted: No
In the wild: Yes

OVERVIEW

Infection Channel: 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

File Size: 10,908 bytes

File Type: PHP

Memory Resident: Yes

Initial Samples Received Date: 13 Apr 2021

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.

Backdoor Routine

This Backdoor executes the following commands from a remote malicious user:

Delete arbitrary posts
Update arbitrary posts
Create a new post
Download all the posts
Download a specific post
Login as Administrator
Execute arbitrary code
Display all plugins
Disable/Remove a specific plugin
Print plugin name in the site footer
Mask the following site options from being displayed on a page:
- link_post
- oWpResp
- flex
- submitted_info
- __phoneDataType
- percentage_of_total
- xmlProperty
- Add_Tab
- still_online
- eme_date_obj
- product_parcent
- topic_forumid
- opt_kerning

Other Details

This Backdoor does the following:

The backdoor removes itself
The script will run if the following conditions are met:
- HTTP Referer is more than 10 characters and not an internal referer
- Stored browser cookies are greater than zero
- User agents are not any of the following:
It can choose 3 random third-party sites and inject malicious script into the webpages
It can add a scheduled task, named "dolly_event", that will occur daily
- It will update the 'flex' content from the third-party sites
It will attempt to add an admin user to the site database

It requires being hosted on a web server in order to proceed with its intended routine.

SOLUTION

Minimum Scan Engine: 9.800

FIRST VSAPI PATTERN FILE: 16.654.06

FIRST VSAPI PATTERN DATE: 13 Apr 2021

VSAPI OPR PATTERN File: 16.655.00

VSAPI OPR PATTERN Date: 14 Apr 2021

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

Identify and terminate files detected as Backdoor.PHP.DOLLYWAY.A

[ Learn More ]

Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 3

Scan your computer with your Trend Micro product to delete files detected as Backdoor.PHP.DOLLYWAY.A. 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:

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Backdoor.PHP.DOLLYWAY.A

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SOLUTION

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