is a generic host
process name for a group of services that are run from dynamic-link libraries (DLLs) and can run other services underneath itself. This is a valid system process that belongs to the Windows Operating System which handles processes executed from .dll's
. It runs from the registry key, HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Svchost where details of the services running under each instance of svchost.exe can be found. At startup, Svchost.exe checks the services portion of the registry to construct a list of services that it needs to load. It is not unusual to find multiple instances of Svchost.exe running at the same time
in Task Manager
in order to optimize the running of the various services.
- svchost.exe SYSTEM
- svchost.exe LOCAL SERVICE
- svchost.exe NETWORK SERVICE
Each Svchost.exe session can contain a grouping of services, therefore, separate services can run, depending on how and where Svchost.exe is started. This grouping of services permits better control and easier debugging. The process ID's (PID's) are not static and can change with each logon but generally they stay nearly the same because they are running services all the time. The PID's must be checked in real time to determine what services each instance of svchost.exe is controlling at that particular time.
Determining whether a file is malware or a legitimate process usually depends on the location
(path) it is running from. One of the ways that malware tries to hide is to give itself the same name as a critical system file like svchost.exe. However, it then places itself in a different location (folder) than where the legitimate file resides and runs from there. In Windows XP and Vista, the legitimate Svchost.exe file is located in the C:\WINDOWS\system32\ folder.
Another techinique is for the process to alter the registry and add itself as a service
or startup program as shown here
so that it can run automatically each time the computer is booted. Keep in mind that a legitimate file can also be infected by some types of malware such as Virut
which is a dangerous polymorphic file infector
When investigating svchost.exe, always make sure the spelling
is correct. If it's scv
host.exe, then your dealing with a Trojan
There are several ways to investigate and see what services a Svchost.exe process is controlling:
Since you are experiencing redirects, please follow these instructions: How to remove Google Redirects or the TDSS, TDL3, Alureon rootkit using TDSSKiller
-- For any files detected as 'Suspicious', get a second opinion by submitting to Jotti's virusscan or VirusTotal. In the "File to upload & scan" box, browse to the location of the suspicious file and submit (upload) it for scanning/analysis.
- If malicious objects are found, they will show in the Scan results - Select action for found objects and offer three options.
- Ensure Cure is selected, then click Continue > Reboot now to finish the cleaning process. <- Important!!
Note: If 'Suspicious' objects are detected, you will be given the option to Skip or Quarantine. Skip will be the default selection.
- A log file named TDSSKiller_version_date_time_log.txt (i.e. TDSSKiller.184.108.40.206_20.07.2010.08.26.56_log.txt) will be created and saved to the root directory (usually Local Disk C:).
- Copy and paste the contents of that file in your next reply.