RANSOM_CRYPCUTE.A
Win32.Trojan-Ransom.Filecoder.P@gen (GData)
Windows
Threat Type: Trojan
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
TECHNICAL DETAILS
Arrival Details
This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.
Installation
This Trojan drops the following files:
- {malware path}\sendBack.txt - contains RSA key value
- {malware path}\secret.txt - contains RSA key value
- {malware path}\secretAES.txt - contains encrypted key
- {malware path}\data recive - contains pc name and RSA key value
It adds the following processes:
- It uses rundll32.exe to run a script that adds its registry entry:
- "C:\Windows\System32\rundll32.exe" javascript:"\..\mshtml,RunHTMLApplication ";document.write();shell=new%20ActiveXObject("wscript.shell");shell.regwrite("HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce\uccu","{malware path and filename}"
It adds the following mutexes to ensure that only one of its copies runs at any one time:
- cuteRansomware
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
uccu = "{malware path and filename}"
Other System Modifications
This Trojan modifies the following file(s):
- It encrypts files and names the encrypted files as {random filename}.uccu
It deletes the following files:
- deletes the original files after producing the encrypted files
Other Details
This Trojan encrypts files with the following extensions:
- .png
- .3dm
- .3g2
- .3gp
- .aaf
- .accdb
- .aep
- .aepx
- .aet
- .ai
- .aif
- .arw
- .as
- .as3
- .asf
- .asp
- .asx
- .avi
- .bay
- .bmp
- .cdr
- .cer
- .class
- .cpp
- .cr2
- .crt
- .crw
- .cs
- .csv
- .db
- .dbf
- .dcr
- .der
- .dng
- .doc
- .docb
- .docm
- .docx
- .dot
- .dotm
- .dotx
- .dwg
- .dxf
- .dxg
- .efx
- .eps
- .erf
- .fla
- .flv
- .idml
- .iff
- .indb
- .indd
- .indl
- .indt
- .inx
- .jar
- .java
- .jpeg
- .jpg
- .kdc
- .m3u
- .m3u8
- .m4u
- .max
- .mdb
- .mdf
- .mef
- .mid
- .mov
- .mp3
- .mp4
- .mpa
- .mpeg
- .mpg
- .mrw
- .msg
- .nef
- .nrw
- .odb
- .odc
- .odm
- .odp
- .ods
- .odt
- .orf
- .p12
- .p7b
- .p7c
- .pdb
- .pef
- .pem
- .pfx
- .php
- .plb
- .pmd
- .pot
- .potm
- .potx
- .ppam
- .ppj
- .pps
- .ppsm
- .ppsx
- .ppt
- .pptm
- .pptx
- .prel
- .prproj
- .ps
- .psd
- .pst
- .ptx
- .r3d
- .ra
- .raf
- .rar
- .raw
- .rb
- .rtf
- .rw2
- .rwl
- .sdf
- .sldm
- .sldx
- .sql
- .sr2
- .srf
- .srw
- .svg
- .swf
- .tif
- .vcf
- .vob
- .wav
- .wb2
- .wma
- .wmv
- .wpd
- .wps
- .x3f
- .xla
- .xlam
- .xlk
- .xll
- .xlm
- .xls
- .xlsb
- .xlsm
- .xlsx
- .xlt
- .xltm
- .xltx
- .xlw
- .xml
- .xqx
- .zip
SOLUTION
Step 1
Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.
Step 2
Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.
Step 3
Scan your computer with your Trend Micro product and note files detected as RANSOM_CRYPCUTE.A
Step 4
Restart in Safe Mode
Step 5
Delete this registry value
Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
- uccu = "{malware path and filename}"
- uccu = "{malware path and filename}"
Step 6
Search and delete this file
- {malware path}\sendBack.txt
- {malware path}\secret.txt
- {malware path}\secretAES.txt
- {malware path}\data recive
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_CRYPCUTE.A. 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.
Step 8
Restore encrypted files from backup.
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