TROJ_BREDO.AC
Windows 2000, XP, Server 2003
Threat Type: Trojan
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
This Trojan may be downloaded by other malware/grayware/spyware from remote sites. It may be unknowingly downloaded by a user while visiting malicious websites.
It connects to certain websites to send and receive information.
It poses as an antispyware application that uses pop-up messages displayed on the System Tray to make users think that their systems are infected. This tricks users to purchase the complete version of the said application. It poses as an antispyware application that displays deceptive warnings and misleading scan results. It may also add other applications which it detects upon its installation. When users agree to buy the software, it connects to a certain URL.
TECHNICAL DETAILS
Arrival Details
This Trojan may be downloaded by other malware/grayware/spyware from remote sites.
It may be unknowingly downloaded by a user while visiting malicious websites.
Installation
This Trojan drops the following copies of itself into the affected system:
- %Application Data%\{random characers}.exe
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
{malware filename} = %Aplication Data%\{malware filename}.exe 0 {random number}
Other Details
This Trojan connects to the following website to send and receive information:
- http://{BLOCKED}.{BLOCKED}.117.67/cb_soft.php?
It displays the following images:
It does the following:
- It supports multiple languages, which further tricks the users into thinking that the application is legitimate.
- It displays a deceptive warning.
- It displays a pop-up message on the system tray.
- It intercepts the execution of .EXE files and displays a message box informing users that the application they are trying to run is infected by a virus.
Rogue Antivirus Routine
This Trojan displays the following fake alerts:
It poses as an antispyware application that uses pop-up messages on the System Tray to make users think that their systems are infected. This tricks users to purchase the complete version of the said application.
It poses as an antispyware application that displays deceptive warnings and misleading scan results. It may also add other applications which it detects upon its installation.
When users agree to buy the software, it connects to the following URL to continue the purchase:
- http://{BLOCKED}edpaymentgate.com/buy.php?
SOLUTION
Step 1
For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.
Step 2
Scan your computer with your Trend Micro product and note files detected as TROJ_BREDO.AC
Step 3
Restart in Safe Mode
Step 4
Delete the registry entry with an unknown data value
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.
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnceStep 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_BREDO.AC. 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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