SWF_DLOADER.WYAA


 ALIASES:

SWF/TrojanDownloader.Esaprof.A (ESET)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet


This Trojan executes when a user accesses certain websites where it is hosted.

  TECHNICAL DETAILS

File Size:

2,167 bytes

File Type:

SWF

Memory Resident:

Yes

Initial Samples Received Date:

04 Jan 2014

Payload:

Connects to URLs/IPs, Downloads files

Arrival Details

This Trojan executes when a user accesses certain websites where it is hosted.

Installation

This Trojan creates the following folders:

  • {drive}\Photo
    where {drive} can be any of the following:
    • D
    • E
    • F
    • G
    • H
    • I
    • J
    • K
    • L
    • M

NOTES:

The following sites contain the configuration data where this Trojan downloads an arbitrary file:

  • http://www.{BLOCKED}se.ru/photo.txt?+{time value}
  • http://www.{BLOCKED}ess.ru/photo.txt?+{time value}
  • http://www.{BLOCKED}tist.ru/photo.txt?+{time value}

Upon accessing the sites, the configuration data contains the following:

As of this writing, it downloads an arbitrary file from the URL http://u10374.{BLOCKED}s.hc.ru/test1.zip as file2.exe.

It creates the following registry entry to enable automatic execution of the downloaded component every startup:

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
Startup = "%Start Menu%\Programs\{file name}.exe"

It drops a copy of the downloaded file in the {drive}\Photo\{file name}.exe. It reports the computer name and operating system version to the site http://www.{BLOCKED}se.ru/photo.php?pc={computer name windows OS version}.

  SOLUTION

Minimum Scan Engine:

9.700

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

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

Close all opened browser windows

Step 4

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

 
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Startup = "%Start Menu%\Programs\{filename}.exe"

Step 5

Search and delete these files

[ Learn More ]
There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %Start Menu%\Programs\{filename}.exe
  • {drive}\Photo\{filename}.exe

Step 6

Search and delete these folders

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • {drive}\Photo

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as SWF_DLOADER.WYAA. 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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