RANSOM_CRYPREN.B
Trojan-Ransom.Win32.Crypren.vmo (Kaspersky), Trojan:Win32/Dynamer!ac (Microsoft), Trojan.Crypren!TqdkWs1H6rI (Agnitum)
Windows
Threat Type: Trojan
Destructiveness: No
Encrypted: No
In the wild: Yes
OVERVIEW
Downloaded from the Internet
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 modifies the Internet Explorer Zone Settings.
TECHNICAL DETAILS
344,898 bytes
EXE
RAR SFX
Yes
15 Jul 2015
Encrypts files, Displays message/message boxes
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 and executes the following files:
- %User Profile%\32.exe
(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.)
It adds the following mutexes to ensure that only one of its copies runs at any one time:
- My_Program_Already_Present
Autostart Technique
This Trojan drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:
- %User Startup%\3.lnk
(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)
Web Browser Home Page and Search Page Modification
This Trojan modifies the Internet Explorer Zone Settings.
Dropping Routine
This Trojan drops the following files:
- {Folder Path Visited}\help-decrypr-file.enc
- %User Profile%\3.png
Other Details
This Trojan displays the following message boxes:
It encrypts files with the following extensions:
- .bkp
- .blend
- .bpw
- .c
- .cdr
- .cdf
- .cdr3
- .cdr5
- .cdr4
- .cdr6
- .cdrw
- .cdx
- .ce1
- .ce2
- .cer
- .cfp
- .cgm
- .cib
- .cls
- .cmt
- .cpi
- .craw
- .crt
- .csh
- .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
- .h
- .hbk
- .hpp
- .ibank
- .idb
- .ibz
- .idx
- .iiq
- .incpas
- .jpg
- .jpeg
- .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
- .ra2
- .raf
- .rar
- .raw
- .rdb
- .rtf
- .rwl
- .rw2
- .rwz
- .s3db
- .sas7bdat
- .sav
- .sdo
- .sd1
- .sda
- .sdf
- .sldm
- .sldx
- .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
- .3ds
- .3fr
- .3pr
- .7z
- .ab4
- .ac2
- .accdb
- .accde
- .accdr
- .accdt
- .acr
- .adb
- .agd1
- .ai
- .ait
- .al
- .apj
- .arw
- .asp
- .awg
- .backup
- .backupdb
- .bak
- .bdb
- .bgt
- .bik
- .xls
- .xlsx
- .xlsb
- .xlsm
- .xlt
- .xltm
- .xltx
- .xlw
- .xml
- .ycbcra
- .zip
- .JPG
- .JPEG
- .mp3
It renames encrypted files using the following names:
- {Original File name and Extension}.{BLOCKED}@INDIA.COM
NOTES:
This Trojan finds files to encrypt in the following drives:
- C:\
- D:\
- E:\
- F:\
- G:\
- H:\
- T:\
SOLUTION
9.750
11.820.03
29 Jul 2015
11.821.00
30 Jul 2015
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
Search and delete this file
- %User Profile%\32.exe
- %User Profile%\3.png
- %User Startup%\3.lnk
- help-decrypr-file.enc
Step 4
Scan your computer with your Trend Micro product to delete files detected as RANSOM_CRYPREN.B. 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 5
Reset Internet security settings
Step 6
Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.
- Encrypted Files
Did this description help? Tell us how we did.