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TrojanDownloader:Win32/Nefhop.A

First posted on 07 July 2015.
Source: Microsoft

Aliases :

There are no other names known for TrojanDownloader:Win32/Nefhop.A.

Explanation :

Threat behavior

Installation
This threat can create files on your PC, including:

• \fange\10019087malware.exe
• %APPDATA% \roaming\microsoft\internet explorer\quick launch\launch internet explorer browser.lnk

The malware uses code injection to make it harder to detect and remove. It can inject code into running processes.



Payload


Downloads malware or unwanted software

This threat can download other malware and unwanted software onto your PC.

Changes web browser settings


It can change your Internet Explorer start page by modifying the following registry entry:

In subkey: HKCU\Software\Microsoft\Internet Explorer\Main
Sets value: "Start Page"
With data: "http://www.2345.com/?k52796966"

In subkey: HKCU\Software\Microsoft\Internet Explorer\Main
Sets value: "Start Page"
With data: "http://www.2345.com/?k82582792"

In subkey: HKCU\Software\Microsoft\Internet Explorer\Main
Sets value: "Start Page"
With data: "http://www.2345.com/?kcffeige"

Connects to a remote host

We have seen this threat connect to a remote host, including:

• www.341wg.com using port 53
• www.520cf.cc using port 53
• yy.com using port 53

Malware can connect to a remote host to do any of the following:

• Check for an Internet connection
• Download and run files (including updates or other malware)
• Report a new infection to its author
• Receive configuration or other data
• Receive instructions from a malicious hacker
• Search for your PC location
• Upload information taken from your PC
• Validate a digital certificate

Additional information

Creates a mutex

This threat can create one or more mutexes on your PC. For example:

• !BrowserEmulation!SharedMemory!Mutex
• c:!users!administrator!appdata!local!microsoft!windows!history!history.ie5!
• c:!users!administrator!appdata!local!microsoft!windows!temporary internet files!content.ie5!
• c:!users!administrator!appdata!roaming!microsoft!windows!cookies!
• c:!users!administrator!appdata!roaming!microsoft!windows!ietldcache!
• ConnHashTable<2612>_HashTable_Mutex
• IESQMMUTEX_0_208

It might use this mutex as an infection marker to prevent more than one copy of the threat running on your PC.



This malware description was published using automated analysis of file SHA1 377634a6120d708f3a09abb5ce44a89d9b3b64ef.

Symptoms

The following can indicate that you have this threat on your PC:

• You see a file similar to:
  • \fange\10019087malware.exe
  • %APPDATA%\roaming\microsoft\internet explorer\quick launch\launch internet explorer browser.lnk
    
    
• You see registry modifications such as:
• In subkey: HKCU\Software\Microsoft\Internet Explorer\Main
  Sets value: "Start Page"
  With data: "http://www.2345.com/?k52796966"
  
  
• In subkey: HKCU\Software\Microsoft\Internet Explorer\Main
  Sets value: "Start Page"
  With data: "http://www.2345.com/?k82582792"
  
  
• In subkey: HKCU\Software\Microsoft\Internet Explorer\Main
  Sets value: "Start Page"
  With data: "http://www.2345.com/?kcffeige"
  
  
• You see the following mutex:
  • !BrowserEmulation!SharedMemory!Mutex
  • c:!users!administrator!appdata!local!microsoft!windows!history!history.ie5!
  • c:!users!administrator!appdata!local!microsoft!windows!temporary internet files!content.ie5!
  • c:!users!administrator!appdata!roaming!microsoft!windows!cookies!
  • c:!users!administrator!appdata!roaming!microsoft!windows!ietldcache!
  • ConnHashTable<2612>_HashTable_Mutex
  • IESQMMUTEX_0_208

Last update 07 July 2015

 

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