Dfsvc.exe Malware

[Marine Farinha]

Dfsvcexe is an executable file. It is a part of Windows operating system and its well-known file of Microsoft .net framework. Since it is not an essential file for Windows operationg system, it can be stored anywhere in the hard drive. Since this file is a part of microsoft .net framework, the malware programmers write the malware program and spread the malware via internet.

Since it is not a windows core file, The user installs the software and stores anywhere in the hard disk, Check the task manager by pressing the combination of keys like CTRL+DEL+ALT and go to the process tab, right click on the dfsvc.exe process and check the loctation, if the file is found in a different location, then the system is infected with viurs.

How to remove the dfsvc.exe file from system using Comodo Free Antivirus?

Step l: Download our award-winning Comodo Free Antivirus.

Step 2: Installation configuration frames will be displayed. Select the configuration you would like to apply

Step 3: Select Customize Configuration option and arrange installers, configuration, and file location.

Step 4: Once the Installation is Finished, restart your PC.

Step 5: It will take some time for the Comodo Internet Security to update the antivirus.

Step 6: Proceed with a quick scan that automatically begins after the update.

Step 7: If threats are found during the scanning, you will be prompted with an alert screen.

Step 8: Comodo Antivirus will remove the dfsvc.exe virus from your computer including all other malwares!

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The .exe extension on a filename indicates an executable file. Executable files may, in some cases, harm your computer. Therefore, please read below to decide for yourself whether the dfsvc.exe on your computer is a Trojan that you should remove, or whether it is a file belonging to the Windows operating system or to a trusted application.

Important: Some malware camouflages itself as dfsvc.exe, particularly when located in the C:\Windows or C:\Windows\System32 folder. Therefore, you should check the dfsvc.exe process on your PC to see if it is a threat. We recommend Security Task Manager for verifying your computer's security. This was one of the Top Download Picks of The Washington Post and PC World.

Summary: Average user rating of dfsvc.exe: based on 26 votes with 17 user comments.8 users think dfsvc.exe is essential for Windows or an installed application.7 users think it's probably harmless.7 users think it's neither essential nor dangerous.3 users suspect danger.One user thinks dfsvc.exe is dangerous and recommends removing it.5 users don't grade dfsvc.exe ("not sure about it").

A clean and tidy computer is the key requirement for avoiding problems with dfsvc. This means running a scan for malware, cleaning your hard drive using 1cleanmgr and 2sfc /scannow, 3uninstalling programs that you no longer need, checking for Autostart programs (using 4msconfig) and enabling Windows' 5Automatic Update. Always remember to perform periodic backups, or at least to set restore points.

Should you experience an actual problem, try to recall the last thing you did, or the last thing you installed before the problem appeared for the first time. Use the 6resmon command to identify the processes that are causing your problem. Even for serious problems, rather than reinstalling Windows, you are better off repairing of your installation or, for Windows 8 and later versions, executing the 7DISM.exe /Online /Cleanup-image /Restorehealth command. This allows you to repair the operating system without losing data.

To help you analyze the dfsvc.exe process on your computer, the following programs have proven to be helpful: ASecurity Task Manager displays all running Windows tasks, including embedded hidden processes, such as keyboard and browser monitoring or Autostart entries. A unique security risk rating indicates the likelihood of the process being potential spyware, malware or a Trojan. BMalwarebytes Anti-Malware detects and removes sleeping spyware, adware, Trojans, keyloggers, malware and trackers from your hard drive.

Scan your computer with your Trend Micro product to delete files detected as WORM_RENAMER.AD. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.

Restore deleted/modified files and/or registry entries from backup *Note: Only Microsoft-related files/keys/values will be restored. If this malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

In part one of this research, the Cybereason Nocturnus Incident Response Team provided a unique glimpse into the Winnti intrusion playbook, covering the techniques that were used by the group from initial compromise to stealing the data, as observed and analyzed by the Cybereason Incident Response team.

This part of the research zeroes in on the Winnti malware arsenal that was discovered during the investigation conducted by the Cybereason IR and Nocturnus teams. In addition, our analysis of the observed malware provides a deeper understanding of the elaborate and multi-layered Winnti infection chain, including evasive maneuvers and stealth techniques that are baked-in to the malware code, as well as the functionality of the various malware.

These steps have proven themselves effective time and time again, as the operation remained under-the-radar for years. While there have been past reports describing some aspects of these intrusions, at the time of writing this report there was no publicly available research that discussed all of the tools and techniques and the manner in which they all fit together, as mentioned in this report.

If it does, the loader checks for its size: if it is larger than 1.04 MB, it deletes it; if it is smaller than 1.04 MB or equal to it, it decrypts it in memory using the open-source CryptoPP C++ library and then deletes it from disk.

The BypassEdrHook function will compare the first bytes in memory of the native API functions in the loaded ntdll.dll image to the first bytes in memory of the same function in the loaded/copied DLL memory image.

To override it, the attackers count the number of different bytes at the beginning of these two functions, then they change the permissions of the relevant patched bytes in the original ntdll.dll image to READWRITE_EXECUTE, copy the original bytes from the loaded/copied DLL memory, and restore the previous page protection settings:

Moreover, our PE files also share a similar evasion technique in masquerading as a legitimate executable. In the aforementioned blog post, it disguised as D3D DLL - a Direct3D 11 runtime DLL, now it disguise as SQLite3:

After deploying the initial payload, Winnti employs a sophisticated and unique multi-staged infection chain with numerous payloads. Each payload fulfills a unique role in the infection chain, which is successful only upon the complete deployment of all of the payloads.

Several unique techniques are used by the Winnti group to store data, evade detection, and thwart investigations during this infection flow. One of those techniques, which Winnti heavily uses, is the CLFS mechanism.

One of the main uses of CLFS in the Windows operating system is in the Windows Kernel Transaction Manager (KTM) for both Transactional NTFS (TxF) and Transactional Registry (TxR) operations. Transactional operations bring the concept of atomic transactions to Windows, allowing Windows to log different operations on those components and support the ability to roll back if needed.

CLFS employs a proprietary file format that isn't documented, and can only be accessed through the CLFS API functions. As of writing this report, there is no tool which can parse the flushed logs. This is a huge benefit for attackers, as it makes it more difficult to examine and detect them while using the CLFS mechanism.

Throughout the execution, STASHLOG uses the same string decryption technique used in other samples by XORing strings with pre-defined bytes, words or qwords, using the XMM registers. This decryption sequence is present at the beginning of every function that uses strings, where those strings are not saved globally, likely in an attempt to protect them.

This sample uses an interesting Anti-Disassembly technique which thwarts the disassembly process and makes the investigation job harder. Each function inside STASHLOG contains a jump list of every node in the function:

SPARKLOG (spark.exe) is a 32 bit executable written in C++, employed in this attack to extract a DLL from the CLFS file, decrypt it and then launch it for side-loading by Windows services running as SYSTEM. Executing this phase of the attack successfully enables the attackers to gain Privilege Escalation and also Persistence in a specific case.

The PE then retrieves an encrypted DLL content from the CLFS log file, decrypts it and gets the OS version in use. This OS version will be required later to understand how to deploy the DLL in the compromised machine. Then, it decrypts the strings Global\HVID_ and Global\APCI#. First, it uses the GetVolumeNameForVolumeMountPointA API call to get the GUID of the operating system volume and acquires a handle to a HVID_ event.

Then, it queries the MachineGUID value from the registry HKLM\SOFTWARE\Microsoft\Cryptography key and creates an event by the name of Global\APCI#. Using these events is a means of communication between the modules in the attack, and it will be used in further modules as well:

Next, it starts to deploy PRIVATELOG based on the OS version. From Windows Vista to Windows 7, SPARKLOG uses a popular DLL side loading technique that involves dropping the DLL with the name wlbsctrl.dll to the %SYSTEM32%\WindowsPowershell\v1.0 directory. It then stops IKEEXT, a service that was compromised by WINNTI in the past, changes the configuration using ChangeServiceConfigA based on the argument count, then starts it again:

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