Backdoor:Win32/Qakbot.gen!A is a generic detection for a trojan backdoor that connects to a remote server, allowing an attacker to access the infected system. By allowing remote access, this backdoor trojan can perform several actions including stealing information and logging user keystrokes. Some variants of this malware may attempt to spread to open shares across a network, including the default shares C$ and Admin$.
System Changes
The following system changes may indicate the presence of this malware:
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The presence of the following files:
%ALLUSERSPROFILE%\qbothome\qbotinj.exe
%ALLUSERSPROFILE%\qbothome\qbotnti.exe
%ALLUSERSPROFILE%\qbothome\qbot.dll
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The presence of the following registry modification:
Modified value: "<program name>"
With data: ""%ALLUSERSPROFILE%\qbothome\qbotinj.exe" "%ALLUSERSPROFILE%\qbothome\qbot.dll" /c "<program data>""
To subkey: HKLM\Microsoft\Windows\CurrentVersion\Run
where <program name> is the name of a legitimate program and <program data> is the legitimate data for that particular program in the registry.
Backdoor:Win32/Qakbot.gen!A is a generic detection for a trojan backdoor that connects to a remote server, allowing an attacker to access the infected system. By allowing remote access, this backdoor trojan can perform several actions including stealing information and logging user keystrokes. Some variants of this malware may attempt to spread to open shares across a network, including the default shares C$ and Admin$.
Installation
Backdoor:Win32/Qakbot.gen!A may be downloaded and installed by other malware. It may be hosted on a number of malicious domains as the following file:
<site>/cgi-bin/jl/jloader.pl?u=u/_qbotinj.exe
where <site> is the malicious domain.
Upon execution, it creates the mutex '_qbot.*' to ensure that only one instance of itself is currently running. Backdoor:Win32/Qakbot.gen!A creates the following files, which are all detected as Backdoor:Win32/Qakbot.gen!A:
- %ALLUSERSPROFILE%\qbothome\qbotinj.exe
- %ALLUSERSPROFILE%\qbothome\qbotnti.exe
- %ALLUSERSPROFILE%\qbothome\qbot.dll
- %ALLUSERSPROFILE%\qbothome\q1.<number>
The registry is commonly modified to execute one of the backdoor components at each Windows start, for example:
Modifies value: "<program name>"
With data: ""%ALLUSERSPROFILE%\qbothome\qbotinj.exe" "%ALLUSERSPROFILE%\qbothome\qbot.dll" /c "<program data>""
To subkey: HKLM\Microsoft\Windows\CurrentVersion\Run
where <program name> is the name of a legitimate program and <program data> is the legitimate data for that particular program in the registry. The malware creates a batch script pointing to the installed copy of Win32/Qakbot as the following:
%USERPROFILE%\Start Menu\Programs\Startup\startup.bat.
When Windows starts, the file 'startup.bat' executes Win32/Qakbot.
Payload
Performs backdoor functionality
Backdoor:Win32/Qakbot.gen!A attempts to connect to a remote server to receive command instructions from an attacker. Commands could include any of the following actions:
- Log keystrokes
- Get the host's IP address and name
- Steal cookies and certificates
- Monitor Favorites and visited URLs
- Steal passwords from Internet Explorer, MSN Messenger, and Outlook
- Steal Autocomplete information
Some of the observed domains this backdoor connects to are 'w1.webinspector.biz' and 'cdcdcdcdc2121cdsfdfd.com'.
Downloads Malware
Win32/Qakbot attempts to download additional files or updates from predefined remote servers. Updates may be requested as password protected ZIP archives. In the wild, this trojan was observed to request an update as "qa.zip" from a malicious site. The malware also downloads configuration files with filenames such as the following:
crontab.cb
updates.cb
updates1.cb
updates<random>_new.cb
_qbot.cb
Analysis by Huzefa Mogri
Take the following steps to help prevent infection on your system:
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Enable a firewall on your computer.
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Get the latest computer updates for all your installed software.
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Use up-to-date antivirus software.
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Use caution when opening attachments and accepting file transfers.
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Use caution when clicking on links to web pages.
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Avoid downloading pirated software.
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Protect yourself against social engineering attacks.
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Use strong passwords.
Enable a firewall on your computer
Use a third-party firewall product or turn on the Microsoft Windows Internet Connection Firewall.
To turn on the Windows Firewall in Windows Vista
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Click Start, and click Control Panel.
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Click Security.
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Click Turn Windows Firewall on or off.
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Select On.
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Click OK.
To turn on the Internet Connection Firewall in Windows XP
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Click Start, and click Control Panel.
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Click Network and Internet Connections. If you do not see Network and Internet Connections, click Switch to Category View.
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Click Change Windows Firewall Settings.
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Select On.
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Click OK.
Get the latest computer updates
Updates help protect your computer from viruses, worms, and other threats as they are discovered. It is important to install updates for all the software that is installed in your computer. These are usually available from vendor websites.
You can use the Automatic Updates feature in Windows to automatically download future Microsoft security updates while your computer is on and connected to the Internet.
To turn on Automatic Updates in Windows Vista
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Click Start, and click Control Panel.
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Click System and Maintainance.
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Click Windows Updates.
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Select a setting. Microsoft recommends selecting Install updates automatically and choose a time that is convenient for you. If you do not choose Automatic, but you choose to be notified when updates are ready, a notification balloon appears when new downloads are available to install. Click the notification balloon to review and install the updates.
To turn on Automatic Updates in Windows XP
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Click Start, and click Control Panel.
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Click System.
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Click Automatic Updates.
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Select a setting. Microsoft recommends selecting Automatic. If you do not choose Automatic, but you choose to be notified when updates are ready, a notification balloon appears when new downloads are available to install. Click the notification balloon to review and install the updates.
Use up-to-date antivirus software
Most antivirus software can detect and prevent infection by known malicious software. To help protect you from infection, you should always run antivirus software that is updated with the latest signature files. Antivirus software is available from several sources. For more information,
see http://www.microsoft.com/protect/computer/viruses/vista.mspx.
Use caution when opening attachments and accepting file transfers
Exercise caution with e-mail and attachments received from unknown sources, or received unexpectedly from known sources. Use extreme caution when accepting file transfers from known or unknown sources.
Use caution when clicking on links to Web pages
Exercise caution with links to web pages that you receive from unknown sources, especially if the links are to a Web page that you are not familiar with, unsure of the destination of, or suspicious of. Malicious software may be installed in your system simply by visiting a Web page with harmful content.
Avoid downloading pirated software
Threats may also be bundled with software and files that are available for download on various torrent sites. Downloading "cracked" or "pirated" software from these sites carries not only the risk of being infected with malware, but is also illegal. For more information, see '
The risks of obtaining and using pirated software'.
Protect yourself from social engineering attacks
While attackers may attempt to exploit vulnerabilities in hardware or software in order to compromise a system, they also attempt to exploit vulnerabilities in human behavior in order to do the same. When an attacker attempts to take advantage of human behavior in order to persuade the affected user to perform an action of the attacker's choice, it is known as 'social engineering'. Essentially, social engineering is an attack against the human interface of the targeted system. For more information, see '
What is social engineering?'.
Use Strong Passwords
Attackers may try to gain access to your Windows account by guessing your password. It is therefore important that you use a strong password – one that cannot be easily guessed by an attacker. A strong password is one that has at least 8 characters, and combines letters, numbers, and symbols. For more information, see
http://www.microsoft.com/protect/yourself/password/create.mspx.
Recovering from recurring infections on a network
The following additional steps may need to be taken to completely remove this threat from an infected network, and to stop infections from recurring from this and other similar types of network-spreading malware:
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Ensure that an antivirus product is installed on ALL machines connected to the network that can access or host shares (see above for further detail).
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Ensure that all available network shares are scanned with an up-to-date antivirus product.
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Remove any unnecessary network shares or mapped drives.
Note: Additionally it may be necessary to temporarily change the permission on network shares to read-only until the disinfection process is complete.
