TROJ_CRYPLOCK.XW
Win32/Filecoder.DI (ESET-NOD32), Ransom:Win32/Teerac (Microsoft), Trojan.Cryptolocker.E (Symantec)
Windows
Threat Type: Trojan
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
Downloaded from the Internet, Dropped by other malware
This TorrentLocker variant has the capability to double the amount of decryption after its 5-day deadline. It arrives via spam message purporting as a business email that targeted an Australian company.
To get a one-glance comprehensive view of the behavior of this Trojan, refer to the Threat Diagram shown below.
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.
It connects to certain websites to send and receive information.
TECHNICAL DETAILS
423,964 bytes
EXE
Yes
22 Jul 2015
Connects to URLs/IPs, Steals information, Encrypts files
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 copies of itself into the affected system:
- {created folder}\{random folder name}\01000000 - encrypted copy
- %Windows%\{random 8 letters}.exe
(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)
It drops the following file(s)/component(s):
- {created folder}\{random folder name}\00000000
- {created folder}\{random folder name}\02000000
- {created folder}\{random folder name}\03000000 - copy of ransom note
- {created folder}\{random folder name}\04000000
It adds the following processes:
- explorer.exe
It creates the following folders:
- %ProgramData%\{random folder name} - Winodws Vista and Above
- %All Users Profile%\Application Data\{random folder name} - Windows XP and Below
(Note: %ProgramData% is a version of the Program Files folder where any user on a multi-user computer can make changes to programs. This contains application data for all users. This is usually C:\ProgramData in Windows Vista, 7, and 8.. %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000, XP, and Server 2003, or C:\ProgramData on Windows Vista, 7, and 8. )
It injects codes into the following process(es):
- created explorer.exe
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\Run
{random 8 letters} = "%Windows%\{random 8 letters}.exe"
Information Theft
This Trojan gathers the following data:
- Machine GUID
- Computer name
Other Details
This Trojan connects to the following website to send and receive information:
- https://{BLOCKED}on.net/topic.php
It encrypts files with the following extensions:
- 3ds
- 3fr
- 3pr
- 7z
- ab4
- ac2
- accdb
- accde
- accdr
- accdt
- acr
- adb
- agd1
- ai
- ait
- al
- apj
- arw
- asm
- asp
- bak
- bdb
- bgt
- bik
- bkp
- blend
- bpw
- cdf
- cdr
- cdr3
- cdr4
- cdr5
- cdr6
- cdrw
- cdx
- ce1
- ce2
- cer
- cfp
- cgm
- cib
- cls
- cmt
- cpi
- cpp
- cr2
- craw
- crt
- crw
- csh
- csl
- css
- csv
- dac
- db
- db-journal
- db3
- dbf
- dc2
- dcr
- dcs
- ddd
- ddoc
- ddrw
- der
- design
- dgc
- djvu
- dng
- doc
- docm
- docx
- dot
- dotm
- dotx
- drf
- drw
- dwg
- dxb
- erbsql
- erf
- exf
- fdb
- ffd
- fff
- fh
- fhd
- fpx
- fxg
- gray
- grey
- gry
- hbk
- hpp
- ibank
- awg
- backup
- backupdb
- ibd
- ibz
- idx
- iiq
- incpas
- jpeg
- jpg
- js
- kc2
- kdbx
- kdc
- kpdx
- lua
- mdb
- mdc
- mef
- mfw
- mmw
- moneywell
- mos
- mpg
- mrw
- myd
- ndd
- nef
- nop
- nrw
- ns2
- ns3
- ns4
- nsd
- nsf
- nsg
- nsh
- nwb
- nx1
- nx2
- nyf
- odb
- odf
- odg
- odm
- odp
- ods
- odt
- orf
- otg
- oth
- otp
- ots
- ott
- p12
- p7b
- p7c
- pat
- pcd
- pef
- pem
- pfx
- php
- pl
- pot
- potm
- potx
- ppam
- pps
- ppsm
- ppsx
- ppt
- pptm
- pptx
- ps
- psafe3
- psd
- ptx
- py
- ra2
- raf
- rar
- raw
- rdb
- rtf
- rw2
- rwl
- rwz
- s3db
- sas7bdat
- sav
- sd0
- sd1
- sda
- sdf
- sldm
- sldx
- sql
- sqlite
- sqlite3
- sqlitedb
- sr2
- srf
- srw
- st4
- st5
- st6
- st7
- st8
- stc
- std
- sti
- stw
- stx
- sxc
- sxd
- sxg
- sxi
- sxm
- sxw
- txt
- wb2
- x3f
- xla
- xlam
- xll
- xlm
- xls
- xlsb
- xlsm
- xlsx
- xlt
- xltm
- xltx
- xlw
- xml
- ycbcra
- zip
It renames encrypted files using the following names:
- {original file name and extension}.encrypted
NOTES:
It drops the ransom note, DECRYPT_INSTRUCTIONS.html to every directory it encrypts.
It deletes shadow copies by executing the following command:
- vssadmin.exe Delete Shadows /All /Quiet
However, as of this writing, the said sites are inaccessible.
SOLUTION
9.750
Step 1
Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 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
Restart in Safe Mode
Step 4
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\Run
- {random 8 letters} = "%Windows%\{random 8 letters}.exe"
- {random 8 letters} = "%Windows%\{random 8 letters}.exe"
Step 5
Search and delete these folders
- {created folder}\{random folder name}
Step 6
Search and delete these files
- DECRYPT_INSTRUCTIONS.html
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_CRYPLOCK.XW. 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.
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