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Published Jul 06, 2012 | Updated Sep 15, 2017

Worm:Win32/Esfury.W

Detected by Microsoft Defender Antivirus

Aliases: Win32/Injector.TCI (ESET) Trojan.Siggen4.10925 (Dr.Web) Trojan-Ransom.Win32.ZedoPoo.abn (Kaspersky)

Summary

Worm:Win32/Esfury.W is a worm that spreads via removable drives. The worm modifies the Hosts file and a number of security settings, and also terminates and blocks access to a large number of processes. It may also contact a remote server which may instruct it to download and execute arbitrary files. Worm:Win32/Esfury.W belongs to the Worm:Win32/Esfury family of worms.

To detect and remove this threat and other malicious software that may be installed on your computer, run a full-system scan with an appropriate, up-to-date, security solution. The following Microsoft products detect and remove this threat:

Disable Autorun functionality

This threat attempts to spread via removable drives on computers that support Autorun functionality. This is a particularly common method of spreading for many current malware families. For information on disabling Autorun functionality, please see the following article:
http://support.microsoft.com/kb/967715/

Additional remediation steps required for Worm:Win32/Esfury.W

The Domain Name System (DNS) is used (among other things) to map domain names to IP addresses - that is, to map human-readable domain names to machine-readable IP addresses. When a user attempts to visit a particular URL, a browser uses DNS servers to find the correct IP address of the requested domain. When a user is directed to a malicious server that is not part of the authoritative Domain Name System, an attacker can provide incorrect IP addresses at their choice to map to particular domain names, thus directing the user to possibly bogus or malicious sites without the affected user's knowledge.

Worm:Win32/Esfury.W may modify DNS settings on the host computer, thus the following steps may be required after its removal is complete.

If the computer has a network interface that does not receive a configuration using DHCP, reset the DNS configuration if necessary. For information on configuring TCP/IP to use DNS, refer to the following:

Additional remediation instructions for Worm:Win32/Esfury.W

This threat may make lasting changes to a computer's configuration that are NOT restored by detecting and removing this threat. For more information on returning an infected computer to its pre-infected state, please see the following articles:

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