RANSOM_CRYPFINI.A
Ransom:Win32/Finicrypt.A (Microsoft)
Windows
Threat Type: Trojan
Destructiveness: No
Encrypted:
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
496,128 bytes
EXE
17 Nov 2015
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:
- ReadDecryptFilesHere.txt - to all folders with encrypted files
It drops the following copies of itself into the affected system:
- %User Profile%\{Computer Name}{Volume Serial Number}.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.)
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
Microsoft Corporation = "%User Profile%\{Computer Name}{Volume Serial Number}.exe"
Other System Modifications
This Trojan adds the following registry keys:
HKEY_CURRENT_USER\Software\CryptInfinite
HKEY_CURRENT_USER\Software\CryptInfinite\
Info
HKEY_CURRENT_USER\Software\CryptInfinite\
Files
It adds the following registry entries:
HKEY_CURRENT_USER\Software\CryptInfinite\
Info
KEYFREE = "{10 random characters}"
HKEY_CURRENT_USER\Software\CryptInfinite\
Info
KEY = "{70 random characters}"
HKEY_CURRENT_USER\Software\CryptInfinite\
Info
KEYFREE = "{10 random characters}"
HKEY_CURRENT_USER\Software\CryptInfinite\
Info
1 = "000000"
HKEY_CURRENT_USER\Software\CryptInfinite\
Info
c = "23"
HKEY_CURRENT_USER\Software\CryptInfinite\
Info
m = "59"
HKEY_CURRENT_USER\Software\CryptInfinite\
Info
s = "59"
HKEY_CURRENT_USER\Software\CryptInfinite\
Info
FreeFile = "{file name of 10th encrypted file}"
HKEY_CURRENT_USER\Software\CryptInfinite\
Info
Finish = "True"
HKEY_CURRENT_USER\Software\CryptInfinite\
Files
{number starting from 1 until number of encrypted files (multiple entries)} = "{file name of encrypted file}"
Other Details
This Trojan connects to the following possibly malicious URL:
- http://{BLOCKED}6k7iivyki2.onion.direct/lending/bot.php
It renames encrypted files using the following names:
- {original file name and extension}.crinf