Dharma Ransomware Abusing Legitimate Anti-virus Tool to Trick Victims And Infect Their Computers

A new variant of Dharma ransomware masquerading as an ESET AV Remover Installer, to trick the users and to hide its malicious activities.

Dharma ransomware was first found in 2016, and it uses the AES-256 encryption, the ransomware primarily targets storage devices.

A new variant of Dharma ransomware distributed via spam emails, which urges the users to click on the links in the emails. If the user clicks on the link, it prompts for a password that provided in the Email.

Once the user inputs the password, the downloaded files are self-extracting archive named Defender[.]exe, which in turn drops taskhost[.]exe which is the malicious file, also the old version of the renamed ESET AV Remover Defender_nt32_enu[.]exe.

According to TrendMicro analysis, taskhost[.]exe is the file connected with the Dharma ransomware. “The ransomware uses this old ESET AV Remover installer, which appears unmodified based on initial scanning, to divert attention as it encrypts files on the victim’s device.”

It start it’s encryption process in the background once the ESET AV Remover installation begins. It uses ESET GUI onscreen to distract the user, and it processes the encryption in the backend.

The ransomware runs entirely as a separate instance from AV remover, even if the AV remover not executed, the ransomware will run. The AV remover process is to trick the users.

Dharma Ransomware about to encrypt the Following file extension.

.PNG .PSD .PSP .TGA .THM .TIF .TIFF .YUV .AI .EPS .PS .SVG .INDD .PCT .PDF .XLR .XLS .XLSX .ACCDB .DB .DBF .MDB .PDB .SQL .APK .APP .BAT .CGI .COM .EXE .GADGET .JAR .PIF .WSF .DEM .GAM .NES .ROM .SAV .DWG .DXF.GPX .KML .KMZ .ASP .ASPX .CER .CFM .CSR .CSS .HTM .HTML .JS .JSP .PHP .RSS .XHTML. DOC .DOCX .LOG .MSG .ODT .PAGES .RTF .TEX .TXT .WPD .WPS .CSV .DAT .GED .KEY .KEYCHAIN .PPS .PPT .PPTX .INI .PRF .HQX .MIM .UUE .7Z .CBR .DEB .GZ .PKG .RAR .RPM .SITX .TAR.GZ .ZIP .ZIPX .BIN .CUE .DMG .ISO .MDF .TOAST .VCD SDF .TAR .TAX2014 .TAX2015 .VCF .XML .AIF .IFF .M3U .M4A .MID .MP3 .MPA .WAV .WMA .3G2 .3GP .ASF .AVI .FLV .M4V .MOV .MP4 .MPG .RM .SRT .SWF .VOB .WMV 3D .3DM .3DS .MAX .OBJR.BMP .DDS .GIF .JPG ..CRX .PLUGIN .FNT .FON .OTF .TTF .CAB .CPL .CUR .DESKTHEMEPACK .DLL .DMP .DRV .ICNS .ICO .LNK .SYS .CFG, .BZ2, .1CD”

Cybercriminals continue to follow various obfuscation techniques to lure the users, the new variant of Dharma ransomware indicates attackers upgrade old threats and use new techniques.

Indicators of Compromise

SHA256
a5de5b0e2a1da6e958955c189db72467ec0f8daaa9f9f5ccc44e71c6c5d8add4    
703b57adaf02eef74097e5de9d0bbd06fc2c29ea7f92c90d54a0b9a01172babe    
0d7e4d980ae644438ee17c1ea61ac076983ec3efb3cc9d3b588d2d92e52d7c83
083b92a07beebbd9c7d089648b1949f78929410464578a36713033bbd3a8ecea
9ada26a385e8b10f76b7c4f05d591b282bd42e7f429c7bbe7ef0bb0d6499d729
f195983cdf8256f1d1425cc7683f9bf5c624928339ddb4e3da96fdae2657813d
39d3254383e3f49fd3e2dff8212f4b5744d8d5e0a6bb320516c5ee525ad211eb

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