Worm:Win32/Rebhip.K is a worm - a self-propagating program that can spread itself from one computer to another. Worms may spread themselves via a variety of different channels in order to compromise new computers. Commonly, worms may spread directly by copying themselves to removable or network drives, or by attempting to exploit particular vulnerabilities on targeted computers. Worms also often attempt to spread via platforms that require user interaction in order to run. They may send themselves as an attachment to an email or an instant message, or send a link to a copy of themselves in the body of a message. In these cases the message needs to be convincing enough to encourage the victim to click on the link or attachment and run or download a copy of the worm.
Installation
When executed, Worm:Win32/Rebhip.K copies itself to <system folder>\windowsupdate\winupd.exe.
Note: <system folder> refers to a variable location that is determined by the malware by querying the Operating System. The default installation location for the System folder for Windows 2000 and NT is C:\Winnt\System32; and for XP, Vista, and 7 is C:\Windows\System32.
The malware modifies the following registry entries to ensure that its copy executes at each Windows start:
Adds value: "HKLM"
With data: "c:\windows\system32\windowsupdate\winupd.exe"
To subkey: HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
Adds value: "HKCU"
With data: "c:\windows\system32\windowsupdate\winupd.exe"
To subkey: HKCU\Software\Microsoft\windows\currentversion\run
Adds value: "Policies"
With data: "c:\windows\system32\windowsupdate\winupd.exe"
To subkey: HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\Explorer\Run
Adds value: "Policies"
With data: "c:\windows\system32\windowsupdate\winupd.exe"
To subkey: HKCU\Software\Microsoft\Windows\CurrentVersion\policies\Explorer\Run
Adds value: StubPath
With data: "c:\windows\system32\windowsupdate\winupd.exe"
To subkey: hklm\software\microsoft\active setup\installed components\{433n21vu-dkvk-m58q-j281-4hl8d84dgnux}
The malware creates the following files on an affected computer:
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c:\documents and settings\administrator\application data\administratorlog.dat
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c:\documents and settings\administrator\local settings\temp\administrator2.txt
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c:\documents and settings\administrator\local settings\temp\administrator7
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c:\documents and settings\administrator\local settings\temp\administrator8
The malware utilizes code injection in order to hinder detection and removal. When Worm:Win32/Rebhip.K executes, it may inject code into running processes, including the following, for example:
Payload
Modifies browser settings
Worm:Win32/Rebhip.K locks the Internet Explorer toolbar by making the following registry modification:
Adds value:
"Locked" With data:
"1"To subkey:
HKCU\Software\Microsoft\Internet Explorer\Toolbar
Contacts remote host
The malware may contact a remote host at melone.zapto.org using port 80. Commonly, malware may contact a remote host for the following purposes:
- To report a new infection to its author
- To receive configuration or other data
- To download and execute arbitrary files (including updates or additional malware)
- To receive instruction from a remote attacker
- To upload data taken from the affected computer
This malware description was produced and published using our automated analysis system's examination of file SHA1 4441a04c0f8c49f4db2417b5fdc38bc718a97fa9.
