ALIASES:

Ransom:Win32/Crowti.A (Microsoft); Trojan.Cryptodefense (Symantec); Trojan-Spy.Win32.Zbot.ujvn (Kaspersky); Troj/Agent-AJJU (Sophos); Win32.Malware!Drop (Sunbelt)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • 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.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size: 266,240 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 28 Oct 2014

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.

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
ecfed7 = "%System Root%\ecfed78\ecfed78.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
ecfed78 = "%User Profile%\Application Data\ecfed78.exe"

Other System Modifications

This Trojan modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SystemRestore
DisableSR = "1"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Eventlog\Application\
ESENT
EventMessageFile = "%System%\ESENT.dll"

(Note: The default value data of the said registry entry is {random values}.)

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Eventlog\Application\
ESENT
CategoryMessageFile = "%System%\ESENT.dll"

(Note: The default value data of the said registry entry is {random values}.)

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Eventlog\Application\
ESENT
CategoryCount = "1"

(Note: The default value data of the said registry entry is 10.)

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Eventlog\Application\
ESENT
TypesSupported = "7"

(Note: The default value data of the said registry entry is 7.)

Dropping Routine

This Trojan drops the following files:

  • %System Root%\ecfed78\ecfed78.exe
  • %User Profile%\Application Data\ecfed78.exe
  • %User Startup%\ecfed78.exe
  • %User Startup%\ecfed78.exe:1
  • %User Profile%\Application Data\ecfed78.exe:1
  • %System Root%\ecfed78\ecfed78.exe:1

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %User Profile% is a user's profile folder, where it usually is C:\Documents and Settings\{user name} on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name} on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://www.{BLOCKED}apmak.com/kf4bv
  • http://{BLOCKED}yip.com/text
  • {BLOCKED}.73.42
  • {BLOCKED}0.1
  • {BLOCKED}.32.5
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  • {BLOCKED}21.38
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  • {BLOCKED}.186.68
  • {BLOCKED}.120.27
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  • {BLOCKED}59.74
  • {BLOCKED}0.149.4
  • {BLOCKED}9.11
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  • {BLOCKED}.11.7
  • {BLOCKED}.238.185
  • {BLOCKED}.12.245
  • {BLOCKED}213.25
  • {BLOCKED}.210.11
  • {BLOCKED}.223.145
  • {BLOCKED}0.94.49
  • {BLOCKED}232.121
  • {BLOCKED}.100.226
  • {BLOCKED}.44.172
  • {BLOCKED}.114.46
  • {BLOCKED}4.246
  • {BLOCKED}5.94.105
  • {BLOCKED}6.146.88
  • {BLOCKED}0.241.70
  • {BLOCKED}236.206
  • {BLOCKED}4.109.221
  • {BLOCKED}.193.145
  • {BLOCKED}.124.42
  • {BLOCKED}75.84
  • {BLOCKED}.246.23
  • {BLOCKED}0.225.174
  • {BLOCKED}.86.26
  • {BLOCKED}.82.177
  • {BLOCKED}3.48.36
  • {BLOCKED}.223.36
  • {BLOCKED}6.85.155
  • {BLOCKED}3.50.26
  • {BLOCKED}.110.199
  • {BLOCKED}.33.8
  • {BLOCKED}.19.133
  • {BLOCKED}0.168.95
  • {BLOCKED}.164.243
  • {BLOCKED}1.84.222
  • {BLOCKED}42.110
  • {BLOCKED}5.172.244
  • {BLOCKED}4.104.134
  • {BLOCKED}4.91.139
  • {BLOCKED}.46.97
  • {BLOCKED}83.96
  • {BLOCKED}23.152
  • {BLOCKED}4.251.21
  • {BLOCKED}.51.232
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  • {BLOCKED}.98.5
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  • {BLOCKED}.205.63
  • {BLOCKED}.51.46
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  • {BLOCKED}.122.89
  • {BLOCKED}1.233.221
  • {BLOCKED}6.192.48
  • {BLOCKED}9.125.226
  • {BLOCKED}4.184.203
  • {BLOCKED}176.158
  • {BLOCKED}.83.49
  • {BLOCKED}4.114.185
  • {BLOCKED}.53.250
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  • {BLOCKED}.99.251
  • {BLOCKED}188.202
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  • {BLOCKED}.107.91
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  • {BLOCKED}1.237.79
  • {BLOCKED}.186.94
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  • {BLOCKED}.82.25
  • {BLOCKED}.64.7
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  • {BLOCKED}.158.5
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  • {BLOCKED}143.144
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  • {BLOCKED}.141.139
  • {BLOCKED}.70.53
  • {BLOCKED}.63.114
  • {BLOCKED}.78.107
  • {BLOCKED}.182.206
  • {BLOCKED}.166.194
  • {BLOCKED}.144.4
  • {BLOCKED}9.46.173
  • {BLOCKED}238.250
  • {BLOCKED}.129.251
  • {BLOCKED}4.207.215
  • {BLOCKED}4.203.103
  • {BLOCKED}239.187
  • {BLOCKED}.96.78
  • {BLOCKED}4.0.100
  • {BLOCKED}1.40.50

It deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.700

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

Restart in Safe Mode

[ Learn More ]

Step 3

Delete this registry value

[ Learn More ]

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
    • ecfed7 = "%System Root%\ecfed78\ecfed78.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • ecfed78 = "%User Profile%\Application Data\ecfed78.exe"

Step 4

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SystemRestore
    • DisableSR = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Eventlog\Application\ESENT
    • From: EventMessageFile = "%System%\ESENT.dll"
      To: EventMessageFile = ""{random values}""
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Eventlog\Application\ESENT
    • From: CategoryMessageFile = "%System%\ESENT.dll"
      To: CategoryMessageFile = ""{random values}""
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Eventlog\Application\ESENT
    • From: CategoryCount = "1"
      To: CategoryCount = ""10""
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Eventlog\Application\ESENT
    • From: TypesSupported = "7"
      To: TypesSupported = ""7""

Step 5

Search and delete these components

[ Learn More ]
There may be some components that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %System Root%\ecfed78\ecfed78.exe
  • %User Profile%\Application Data\ecfed78.exe
  • %User Startup%\ecfed78.exe
  • %User Startup%\ecfed78.exe:1
  • %User Profile%\Application Data\ecfed78.exe:1
  • %System Root%\ecfed78\ecfed78.exe:1

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_RANSOM.YMJN. 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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