Trojan.Win32.CRYPTODEF.A

February 28, 2020

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:

310,272 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

28 Feb 2020

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
cb8b48 = "%System Root%\cb8b48d\cb8b48d.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
cb8b48d = "%User Profile%\Application Data\cb8b48d.exe"

It drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:

%User Startup%\cb8b48d.exe
%User Startup%\HELP_DECRYPT.TXT
%User Startup%\HELP_DECRYPT.HTML
%User Startup%\HELP_DECRYPT.URL
%User Startup%\HELP_DECRYPT.PNG

(Note: %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, C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows 2003(32-bit), XP and 2000(32-bit), or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit), 10(64-bit).)

Other System Modifications

This Trojan deletes the following files:

%System Root%\cb8b48d

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

It adds the following registry entries:

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D
5k = "{random values}"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D
8u = "{random characters}"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D
3r = "{random characters}"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D
fv = "{random characters}"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\
022334456779CDEE
%User Profile%\Internet Explorer\brndlog.bak = "68adfd"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\
022334456779CDEE
%User Profile%\Internet Explorer\brndlog.txt = "68adfd"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\
022334456779CDEE
%Application Data%\Microsoft\Windows Media\9.0\WMSDKNS.DTD = "68adfd"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\
022334456779CDEE
%User Profile%\Templates\excel.xls = "68adfd"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\
022334456779CDEE
%User Profile%\Templates\excel4.xls = "68adfd"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\
022334456779CDEE
%User Profile%\Templates\powerpnt.ppt = "68adfd"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\
022334456779CDEE
%User Profile%\Templates\quattro.wb2 = "68adfd"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\
022334456779CDEE
%User Profile%\Templates\sndrec.wav = "68adfd"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\
022334456779CDEE
%User Profile%\Templates\winword.doc = "68adfd"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\
022334456779CDEE
%User Profile%\Templates\winword2.doc = "68adfd"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\
022334456779CDEE
%User Profile%\Templates\wordpfct.wpd = "68adfd"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\
022334456779CDEE
%User Profile%\Cookies\wilbert@atdmt[2].txt = "68adfd"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\
022334456779CDEE
%User Profile%\Cookies\wilbert@bing[2].txt = "68adfd"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\
022334456779CDEE
%User Profile%\Cookies\wilbert@c.atdmt[2].txt = "68adfd"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\
022334456779CDEE
%User Profile%\Cookies\wilbert@c.msn[2].txt = "68adfd"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\
022334456779CDEE
%User Profile%\Cookies\wilbert@doubleclick[1].txt = "68adfd"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\
022334456779CDEE
%User Profile%\Cookies\wilbert@microsoft[1].txt = "68adfd"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\
022334456779CDEE
%User Profile%\Cookies\wilbert@msnportal.112.2o7[1].txt = "68adfd"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\
022334456779CDEE
%User Profile%\Cookies\wilbert@msn[2].txt = "68adfd"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\
022334456779CDEE
%User Profile%\Cookies\wilbert@scorecardresearch[2].txt = "68adfd"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\
022334456779CDEE
%User Profile%\Cookies\wilbert@www.bing[2].txt = "68adfd"

HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\
022334456779CDEE
%User Profile%\Cookies\wilbert@www.msn[1].txt = "68adfd"

It modifies the following registry entries:

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

Dropping Routine

This Trojan drops the following files:

%System Root%\cb8b48d\cb8b48d.exe
%User Profile%\Application Data\cb8b48d.exe
A:\HELP_DECRYPT.TXT
A:\HELP_DECRYPT.HTML
%User Profile%\Internet Explorer\brndlog.bak.563
A:\HELP_DECRYPT.URL
%User Profile%\Internet Explorer\brndlog.txt.xn8
%User Profile%\Internet Explorer\HELP_DECRYPT.TXT
%User Profile%\Internet Explorer\HELP_DECRYPT.HTML
%User Profile%\Internet Explorer\HELP_DECRYPT.URL
%User Profile%\Internet Explorer\HELP_DECRYPT.PNG
%User Profile%\Microsoft\HELP_DECRYPT.TXT
%User Profile%\Microsoft\HELP_DECRYPT.HTML
%User Profile%\Microsoft\HELP_DECRYPT.URL
%User Profile%\Microsoft\HELP_DECRYPT.PNG
A:\HELP_DECRYPT.PNG
%User Profile%\Application Data\HELP_DECRYPT.TXT
%User Profile%\Application Data\HELP_DECRYPT.HTML
%User Profile%\Application Data\HELP_DECRYPT.URL
%User Profile%\Application Data\HELP_DECRYPT.PNG
%Application Data%\Microsoft\Windows Media\9.0\WMSDKNS.DTD.y0c
%Application Data%\Microsoft\Windows Media\9.0\HELP_DECRYPT.TXT
%Application Data%\Microsoft\Windows Media\9.0\HELP_DECRYPT.HTML
%Application Data%\Microsoft\Windows Media\9.0\HELP_DECRYPT.URL
%Application Data%\Microsoft\Windows Media\9.0\HELP_DECRYPT.PNG
%Application Data%\Microsoft\Windows Media\HELP_DECRYPT.TXT
%Application Data%\Microsoft\Windows Media\HELP_DECRYPT.HTML
%Application Data%\Microsoft\Windows Media\HELP_DECRYPT.URL
%Application Data%\Microsoft\Windows Media\HELP_DECRYPT.PNG
%Application Data%\Microsoft\HELP_DECRYPT.TXT
%Application Data%\Microsoft\HELP_DECRYPT.HTML
%Application Data%\Microsoft\HELP_DECRYPT.URL
%Application Data%\Microsoft\HELP_DECRYPT.PNG
%Application Data%\HELP_DECRYPT.TXT
%Application Data%\HELP_DECRYPT.HTML
%Application Data%\HELP_DECRYPT.URL
%Application Data%\HELP_DECRYPT.PNG
%User Profile%\Local Settings\HELP_DECRYPT.TXT
%User Profile%\Local Settings\HELP_DECRYPT.HTML
%User Profile%\Local Settings\HELP_DECRYPT.URL
%User Profile%\Local Settings\HELP_DECRYPT.PNG
%User Profile%\Templates\excel.xls.9kn
%User Profile%\Templates\excel4.xls.r95
%User Profile%\Templates\powerpnt.ppt.xt0
%User Profile%\Templates\quattro.wb2.980
%User Profile%\Templates\sndrec.wav.f67
%User Profile%\Templates\winword.doc.u4s
%User Profile%\Templates\winword2.doc.3uo
%User Profile%\Templates\wordpfct.wpd.r34
%User Profile%\Templates\HELP_DECRYPT.TXT
%User Profile%\Templates\HELP_DECRYPT.HTML
%User Profile%\Templates\HELP_DECRYPT.URL
%User Profile%\Templates\HELP_DECRYPT.PNG
%User Profile%\HELP_DECRYPT.TXT
%User Profile%\HELP_DECRYPT.HTML
%User Profile%\HELP_DECRYPT.URL
%User Profile%\HELP_DECRYPT.PNG
%User Profile%\Internet Explorer\brndlog.bak.uo4
%User Profile%\Internet Explorer\brndlog.txt.k92
%User Profile%\Cookies\wilbert@atdmt[2].txt.7w6
%User Profile%\Cookies\wilbert@bing[2].txt.nv4
%User Profile%\Cookies\wilbert@c.atdmt[2].txt.74t
%User Profile%\Cookies\wilbert@c.msn[2].txt.81n
%User Profile%\Cookies\wilbert@doubleclick[1].txt.s77
%User Profile%\Cookies\wilbert@microsoft[1].txt.7i6
%User Profile%\Cookies\wilbert@msnportal.112.2o7[1].txt.yo9
%User Profile%\Cookies\wilbert@msn[2].txt.wr9
%User Profile%\Cookies\wilbert@scorecardresearch[2].txt.75u
%User Profile%\Cookies\wilbert@www.bing[2].txt.1uk
%User Profile%\Cookies\wilbert@www.msn[1].txt.mk0
%User Profile%\Cookies\HELP_DECRYPT.TXT
%User Profile%\Cookies\HELP_DECRYPT.HTML
%User Profile%\Cookies\HELP_DECRYPT.URL
%User Profile%\Cookies\HELP_DECRYPT.PNG
%Application Data%\Microsoft\Windows Media\9.0\WMSDKNS.DTD.24d
%User Profile%\Templates\excel.xls.d6d
%User Profile%\Templates\excel4.xls.4ki
%User Profile%\Templates\powerpnt.ppt.i0q
%User Profile%\Templates\quattro.wb2.k0e
%User Profile%\Templates\sndrec.wav.ck2
%User Profile%\Templates\winword.doc.5ah
%User Profile%\Templates\winword2.doc.4xc
%User Profile%\Templates\wordpfct.wpd.3xx
%System Root%\Documents and Settings\HELP_DECRYPT.TXT
%System Root%\Documents and Settings\HELP_DECRYPT.HTML
%System Root%\Documents and Settings\HELP_DECRYPT.URL
%System Root%\Documents and Settings\HELP_DECRYPT.PNG
%System Root%\HELP_DECRYPT.TXT
%System Root%\HELP_DECRYPT.HTML
%System Root%\HELP_DECRYPT.URL
%System Root%\HELP_DECRYPT.PNG
%Desktop%\HELP_DECRYPT.TXT
%Desktop%\HELP_DECRYPT.HTML
%Desktop%\HELP_DECRYPT.URL
%Desktop%\HELP_DECRYPT.PNG

Other Details

This Trojan connects to the following possibly malicious URL:

http://{BLOCKED}r.es
http://{BLOCKED}com.com/EPSUrj.php?k=30j9ada7npgiy
http://{BLOCKED}com.com/nm9Eul.php?b=30j9ada7npgiy
http://{BLOCKED}com.com/fQu7UH.php?i=30j9ada7npgiy
http://{BLOCKED}com.com/evYR0G.php?m=30j9ada7npgiy
http://{BLOCKED}com.com/R4uGnH.php?t=30j9ada7npgiy
http://{BLOCKED}com.com/EPSUrj.php?v=506e19irnyko
http://{BLOCKED}com.com/nm9Eul.php?s=506e19irnyko
http://{BLOCKED}com.com/fQu7UH.php?k=506e19irnyko
http://{BLOCKED}com.com/evYR0G.php?d=506e19irnyko
http://{BLOCKED}com.com/R4uGnH.php?e=506e19irnyko
http://{BLOCKED}com.com/EPSUrj.php?v=f10i9il9fcw7x5
http://{BLOCKED}com.com/nm9Eul.php?y=f10i9il9fcw7x5
http://{BLOCKED}com.com/fQu7UH.php?y=f10i9il9fcw7x5
http://{BLOCKED}com.com/evYR0G.php?r=f10i9il9fcw7x5
http://{BLOCKED}com.com/R4uGnH.php?v=f10i9il9fcw7x5
http://{BLOCKED}com.com/EPSUrj.php?r=5u16fdys4z
http://{BLOCKED}com.com/nm9Eul.php?d=5u16fdys4z
http://{BLOCKED}com.com/fQu7UH.php?h=5u16fdys4z
http://{BLOCKED}com.com/evYR0G.php?a=5u16fdys4z
http://{BLOCKED}com.com/R4uGnH.php?n=5u16fdys4z
{BLOCKED}5.164.184
{BLOCKED}2.78.160
{BLOCKED}8.215.210
{BLOCKED}8.47.225
{BLOCKED}2.127.240
{BLOCKED}.145.75

It deletes itself after execution.

This report is generated via an automated analysis system.

SOLUTION

Minimum Scan Engine:

9.850

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

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
- cb8b48 = "%System Root%\cb8b48d\cb8b48d.exe"

In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- cb8b48d = "%User Profile%\Application Data\cb8b48d.exe"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D
- 5k = "{random values}"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D
- 8u = "{random characters}"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D
- 3r = "{random characters}"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D
- fv = "{random characters}"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\022334456779CDEE
- %User Profile%\Internet Explorer\brndlog.bak = "68adfd"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\022334456779CDEE
- %User Profile%\Internet Explorer\brndlog.txt = "68adfd"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\022334456779CDEE
- %Application Data%\Microsoft\Windows Media\9.0\WMSDKNS.DTD = "68adfd"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\022334456779CDEE
- %User Profile%\Templates\excel.xls = "68adfd"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\022334456779CDEE
- %User Profile%\Templates\excel4.xls = "68adfd"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\022334456779CDEE
- %User Profile%\Templates\powerpnt.ppt = "68adfd"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\022334456779CDEE
- %User Profile%\Templates\quattro.wb2 = "68adfd"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\022334456779CDEE
- %User Profile%\Templates\sndrec.wav = "68adfd"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\022334456779CDEE
- %User Profile%\Templates\winword.doc = "68adfd"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\022334456779CDEE
- %User Profile%\Templates\winword2.doc = "68adfd"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\022334456779CDEE
- %User Profile%\Templates\wordpfct.wpd = "68adfd"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\022334456779CDEE
- %User Profile%\Cookies\wilbert@atdmt[2].txt = "68adfd"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\022334456779CDEE
- %User Profile%\Cookies\wilbert@bing[2].txt = "68adfd"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\022334456779CDEE
- %User Profile%\Cookies\wilbert@c.atdmt[2].txt = "68adfd"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\022334456779CDEE
- %User Profile%\Cookies\wilbert@c.msn[2].txt = "68adfd"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\022334456779CDEE
- %User Profile%\Cookies\wilbert@doubleclick[1].txt = "68adfd"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\022334456779CDEE
- %User Profile%\Cookies\wilbert@microsoft[1].txt = "68adfd"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\022334456779CDEE
- %User Profile%\Cookies\wilbert@msnportal.112.2o7[1].txt = "68adfd"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\022334456779CDEE
- %User Profile%\Cookies\wilbert@msn[2].txt = "68adfd"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\022334456779CDEE
- %User Profile%\Cookies\wilbert@scorecardresearch[2].txt = "68adfd"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\022334456779CDEE
- %User Profile%\Cookies\wilbert@www.bing[2].txt = "68adfd"

In HKEY_CURRENT_USER\Software\4C583FF312C01233EEC409362342577D\022334456779CDEE
- %User Profile%\Cookies\wilbert@www.msn[1].txt = "68adfd"

To delete the registry value this malware/grayware created:

Open Registry Editor.
» For Windows 7 and Windows Server 2008 (R2) users, click the Start button, type regedit in the Search input field then press Enter.
» For Windows 8, Windows 8.1, Windows 10, and Windows Server 2012 (R2) users, right-click on the lower-left corner of the screen, click Run, type regedit in the text box provided, and then press Enter.
In the left panel, double-click the following:
HKEY_CURRENT_USER>Software>Microsoft>Windows>CurrentVersion>Run
In the right panel, locate and delete the entry:
cb8b48 = "%System Root%\cb8b48d\cb8b48d.exe"
Again In the right panel, locate and delete the entry:
cb8b48d = "%User Profile%\Application Data\cb8b48d.exe"
In the left panel, double-click the following:
HKEY_CURRENT_USER>Software>4C583FF312C01233EEC409362342577D
In the right panel, locate and delete the entry:
5k = "{random values}"
Again In the right panel, locate and delete the entry:
8u = "{random characters}"
Again In the right panel, locate and delete the entry:
3r = "{random characters}"
Again In the right panel, locate and delete the entry:
fv = "{random characters}"
In the left panel, double-click the following:
HKEY_CURRENT_USER>Software>4C583FF312C01233EEC409362342577D>022334456779CDEE
In the right panel, locate and delete the entry:
%User Profile%\Internet Explorer\brndlog.bak = "68adfd"
Again In the right panel, locate and delete the entry:
%User Profile%\Internet Explorer\brndlog.txt = "68adfd"
Again In the right panel, locate and delete the entry:
%Application Data%\Microsoft\Windows Media\9.0\WMSDKNS.DTD = "68adfd"
Again In the right panel, locate and delete the entry:
%User Profile%\Templates\excel.xls = "68adfd"
Again In the right panel, locate and delete the entry:
%User Profile%\Templates\excel4.xls = "68adfd"
Again In the right panel, locate and delete the entry:
%User Profile%\Templates\powerpnt.ppt = "68adfd"
Again In the right panel, locate and delete the entry:
%User Profile%\Templates\quattro.wb2 = "68adfd"
Again In the right panel, locate and delete the entry:
%User Profile%\Templates\sndrec.wav = "68adfd"
Again In the right panel, locate and delete the entry:
%User Profile%\Templates\winword.doc = "68adfd"
Again In the right panel, locate and delete the entry:
%User Profile%\Templates\winword2.doc = "68adfd"
Again In the right panel, locate and delete the entry:
%User Profile%\Templates\wordpfct.wpd = "68adfd"
Again In the right panel, locate and delete the entry:
%User Profile%\Cookies\wilbert@atdmt[2].txt = "68adfd"
Again In the right panel, locate and delete the entry:
%User Profile%\Cookies\wilbert@bing[2].txt = "68adfd"
Again In the right panel, locate and delete the entry:
%User Profile%\Cookies\wilbert@c.atdmt[2].txt = "68adfd"
Again In the right panel, locate and delete the entry:
%User Profile%\Cookies\wilbert@c.msn[2].txt = "68adfd"
Again In the right panel, locate and delete the entry:
%User Profile%\Cookies\wilbert@doubleclick[1].txt = "68adfd"
Again In the right panel, locate and delete the entry:
%User Profile%\Cookies\wilbert@microsoft[1].txt = "68adfd"
Again In the right panel, locate and delete the entry:
%User Profile%\Cookies\wilbert@msnportal.112.2o7[1].txt = "68adfd"
Again In the right panel, locate and delete the entry:
%User Profile%\Cookies\wilbert@msn[2].txt = "68adfd"
Again In the right panel, locate and delete the entry:
%User Profile%\Cookies\wilbert@scorecardresearch[2].txt = "68adfd"
Again In the right panel, locate and delete the entry:
%User Profile%\Cookies\wilbert@www.bing[2].txt = "68adfd"
Again In the right panel, locate and delete the entry:
%User Profile%\Cookies\wilbert@www.msn[1].txt = "68adfd"
Close Registry Editor.

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"

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%\cb8b48d\cb8b48d.exe
%User Profile%\Application Data\cb8b48d.exe
A:\HELP_DECRYPT.TXT
A:\HELP_DECRYPT.HTML
%User Profile%\Internet Explorer\brndlog.bak.563
A:\HELP_DECRYPT.URL
%User Profile%\Internet Explorer\brndlog.txt.xn8
%User Profile%\Internet Explorer\HELP_DECRYPT.TXT
%User Profile%\Internet Explorer\HELP_DECRYPT.HTML
%User Profile%\Internet Explorer\HELP_DECRYPT.URL
%User Profile%\Internet Explorer\HELP_DECRYPT.PNG
%User Profile%\Microsoft\HELP_DECRYPT.TXT
%User Profile%\Microsoft\HELP_DECRYPT.HTML
%User Profile%\Microsoft\HELP_DECRYPT.URL
%User Profile%\Microsoft\HELP_DECRYPT.PNG
A:\HELP_DECRYPT.PNG
%User Profile%\Application Data\HELP_DECRYPT.TXT
%User Profile%\Application Data\HELP_DECRYPT.HTML
%User Profile%\Application Data\HELP_DECRYPT.URL
%User Profile%\Application Data\HELP_DECRYPT.PNG
%Application Data%\Microsoft\Windows Media\9.0\WMSDKNS.DTD.y0c
%Application Data%\Microsoft\Windows Media\9.0\HELP_DECRYPT.TXT
%Application Data%\Microsoft\Windows Media\9.0\HELP_DECRYPT.HTML
%Application Data%\Microsoft\Windows Media\9.0\HELP_DECRYPT.URL
%Application Data%\Microsoft\Windows Media\9.0\HELP_DECRYPT.PNG
%Application Data%\Microsoft\Windows Media\HELP_DECRYPT.TXT
%Application Data%\Microsoft\Windows Media\HELP_DECRYPT.HTML
%Application Data%\Microsoft\Windows Media\HELP_DECRYPT.URL
%Application Data%\Microsoft\Windows Media\HELP_DECRYPT.PNG
%Application Data%\Microsoft\HELP_DECRYPT.TXT
%Application Data%\Microsoft\HELP_DECRYPT.HTML
%Application Data%\Microsoft\HELP_DECRYPT.URL
%Application Data%\Microsoft\HELP_DECRYPT.PNG
%Application Data%\HELP_DECRYPT.TXT
%Application Data%\HELP_DECRYPT.HTML
%Application Data%\HELP_DECRYPT.URL
%Application Data%\HELP_DECRYPT.PNG
%User Profile%\Local Settings\HELP_DECRYPT.TXT
%User Profile%\Local Settings\HELP_DECRYPT.HTML
%User Profile%\Local Settings\HELP_DECRYPT.URL
%User Profile%\Local Settings\HELP_DECRYPT.PNG
%User Profile%\Templates\excel.xls.9kn
%User Profile%\Templates\excel4.xls.r95
%User Profile%\Templates\powerpnt.ppt.xt0
%User Profile%\Templates\quattro.wb2.980
%User Profile%\Templates\sndrec.wav.f67
%User Profile%\Templates\winword.doc.u4s
%User Profile%\Templates\winword2.doc.3uo
%User Profile%\Templates\wordpfct.wpd.r34
%User Profile%\Templates\HELP_DECRYPT.TXT
%User Profile%\Templates\HELP_DECRYPT.HTML
%User Profile%\Templates\HELP_DECRYPT.URL
%User Profile%\Templates\HELP_DECRYPT.PNG
%User Profile%\HELP_DECRYPT.TXT
%User Profile%\HELP_DECRYPT.HTML
%User Profile%\HELP_DECRYPT.URL
%User Profile%\HELP_DECRYPT.PNG
%User Profile%\Internet Explorer\brndlog.bak.uo4
%User Profile%\Internet Explorer\brndlog.txt.k92
%User Profile%\Cookies\wilbert@atdmt[2].txt.7w6
%User Profile%\Cookies\wilbert@bing[2].txt.nv4
%User Profile%\Cookies\wilbert@c.atdmt[2].txt.74t
%User Profile%\Cookies\wilbert@c.msn[2].txt.81n
%User Profile%\Cookies\wilbert@doubleclick[1].txt.s77
%User Profile%\Cookies\wilbert@microsoft[1].txt.7i6
%User Profile%\Cookies\wilbert@msnportal.112.2o7[1].txt.yo9
%User Profile%\Cookies\wilbert@msn[2].txt.wr9
%User Profile%\Cookies\wilbert@scorecardresearch[2].txt.75u
%User Profile%\Cookies\wilbert@www.bing[2].txt.1uk
%User Profile%\Cookies\wilbert@www.msn[1].txt.mk0
%User Profile%\Cookies\HELP_DECRYPT.TXT
%User Profile%\Cookies\HELP_DECRYPT.HTML
%User Profile%\Cookies\HELP_DECRYPT.URL
%User Profile%\Cookies\HELP_DECRYPT.PNG
%Application Data%\Microsoft\Windows Media\9.0\WMSDKNS.DTD.24d
%User Profile%\Templates\excel.xls.d6d
%User Profile%\Templates\excel4.xls.4ki
%User Profile%\Templates\powerpnt.ppt.i0q
%User Profile%\Templates\quattro.wb2.k0e
%User Profile%\Templates\sndrec.wav.ck2
%User Profile%\Templates\winword.doc.5ah
%User Profile%\Templates\winword2.doc.4xc
%User Profile%\Templates\wordpfct.wpd.3xx
%System Root%\Documents and Settings\HELP_DECRYPT.TXT
%System Root%\Documents and Settings\HELP_DECRYPT.HTML
%System Root%\Documents and Settings\HELP_DECRYPT.URL
%System Root%\Documents and Settings\HELP_DECRYPT.PNG
%System Root%\HELP_DECRYPT.TXT
%System Root%\HELP_DECRYPT.HTML
%System Root%\HELP_DECRYPT.URL
%System Root%\HELP_DECRYPT.PNG
%Desktop%\HELP_DECRYPT.TXT
%Desktop%\HELP_DECRYPT.HTML
%Desktop%\HELP_DECRYPT.URL
%Desktop%\HELP_DECRYPT.PNG

To manually delete a malware/grayware file from an affected system:

•For Windows 7, Windows Server 2008 (R2), Windows 8, Windows 8.1, Windows 10, and Windows Server 2012 (R2):

Open a Windows Explorer window.
- For Windows 7 and Server 2008 (R2) users, click Start>Computer.
- For Windows 8, 8.1, 10, and Server 2012 (R2) users, right-click on the lower-left corner of the screen,then click File Explorer.
In the Search Computer/This PC input box, type:
%System Root%\cb8b48d\cb8b48d.exe
%User Profile%\Application Data\cb8b48d.exe
A:\HELP_DECRYPT.TXT
A:\HELP_DECRYPT.HTML
%User Profile%\Internet Explorer\brndlog.bak.563
A:\HELP_DECRYPT.URL
%User Profile%\Internet Explorer\brndlog.txt.xn8
%User Profile%\Internet Explorer\HELP_DECRYPT.TXT
%User Profile%\Internet Explorer\HELP_DECRYPT.HTML
%User Profile%\Internet Explorer\HELP_DECRYPT.URL
%User Profile%\Internet Explorer\HELP_DECRYPT.PNG
%User Profile%\Microsoft\HELP_DECRYPT.TXT
%User Profile%\Microsoft\HELP_DECRYPT.HTML
%User Profile%\Microsoft\HELP_DECRYPT.URL
%User Profile%\Microsoft\HELP_DECRYPT.PNG
A:\HELP_DECRYPT.PNG
%User Profile%\Application Data\HELP_DECRYPT.TXT
%User Profile%\Application Data\HELP_DECRYPT.HTML
%User Profile%\Application Data\HELP_DECRYPT.URL
%User Profile%\Application Data\HELP_DECRYPT.PNG
%Application Data%\Microsoft\Windows Media\9.0\WMSDKNS.DTD.y0c
%Application Data%\Microsoft\Windows Media\9.0\HELP_DECRYPT.TXT
%Application Data%\Microsoft\Windows Media\9.0\HELP_DECRYPT.HTML
%Application Data%\Microsoft\Windows Media\9.0\HELP_DECRYPT.URL
%Application Data%\Microsoft\Windows Media\9.0\HELP_DECRYPT.PNG
%Application Data%\Microsoft\Windows Media\HELP_DECRYPT.TXT
%Application Data%\Microsoft\Windows Media\HELP_DECRYPT.HTML
%Application Data%\Microsoft\Windows Media\HELP_DECRYPT.URL
%Application Data%\Microsoft\Windows Media\HELP_DECRYPT.PNG
%Application Data%\Microsoft\HELP_DECRYPT.TXT
%Application Data%\Microsoft\HELP_DECRYPT.HTML
%Application Data%\Microsoft\HELP_DECRYPT.URL
%Application Data%\Microsoft\HELP_DECRYPT.PNG
%Application Data%\HELP_DECRYPT.TXT
%Application Data%\HELP_DECRYPT.HTML
%Application Data%\HELP_DECRYPT.URL
%Application Data%\HELP_DECRYPT.PNG
%User Profile%\Local Settings\HELP_DECRYPT.TXT
%User Profile%\Local Settings\HELP_DECRYPT.HTML
%User Profile%\Local Settings\HELP_DECRYPT.URL
%User Profile%\Local Settings\HELP_DECRYPT.PNG
%User Profile%\Templates\excel.xls.9kn
%User Profile%\Templates\excel4.xls.r95
%User Profile%\Templates\powerpnt.ppt.xt0
%User Profile%\Templates\quattro.wb2.980
%User Profile%\Templates\sndrec.wav.f67
%User Profile%\Templates\winword.doc.u4s
%User Profile%\Templates\winword2.doc.3uo
%User Profile%\Templates\wordpfct.wpd.r34
%User Profile%\Templates\HELP_DECRYPT.TXT
%User Profile%\Templates\HELP_DECRYPT.HTML
%User Profile%\Templates\HELP_DECRYPT.URL
%User Profile%\Templates\HELP_DECRYPT.PNG
%User Profile%\HELP_DECRYPT.TXT
%User Profile%\HELP_DECRYPT.HTML
%User Profile%\HELP_DECRYPT.URL
%User Profile%\HELP_DECRYPT.PNG
%User Profile%\Internet Explorer\brndlog.bak.uo4
%User Profile%\Internet Explorer\brndlog.txt.k92
%User Profile%\Cookies\wilbert@atdmt[2].txt.7w6
%User Profile%\Cookies\wilbert@bing[2].txt.nv4
%User Profile%\Cookies\wilbert@c.atdmt[2].txt.74t
%User Profile%\Cookies\wilbert@c.msn[2].txt.81n
%User Profile%\Cookies\wilbert@doubleclick[1].txt.s77
%User Profile%\Cookies\wilbert@microsoft[1].txt.7i6
%User Profile%\Cookies\wilbert@msnportal.112.2o7[1].txt.yo9
%User Profile%\Cookies\wilbert@msn[2].txt.wr9
%User Profile%\Cookies\wilbert@scorecardresearch[2].txt.75u
%User Profile%\Cookies\wilbert@www.bing[2].txt.1uk
%User Profile%\Cookies\wilbert@www.msn[1].txt.mk0
%User Profile%\Cookies\HELP_DECRYPT.TXT
%User Profile%\Cookies\HELP_DECRYPT.HTML
%User Profile%\Cookies\HELP_DECRYPT.URL
%User Profile%\Cookies\HELP_DECRYPT.PNG
%Application Data%\Microsoft\Windows Media\9.0\WMSDKNS.DTD.24d
%User Profile%\Templates\excel.xls.d6d
%User Profile%\Templates\excel4.xls.4ki
%User Profile%\Templates\powerpnt.ppt.i0q
%User Profile%\Templates\quattro.wb2.k0e
%User Profile%\Templates\sndrec.wav.ck2
%User Profile%\Templates\winword.doc.5ah
%User Profile%\Templates\winword2.doc.4xc
%User Profile%\Templates\wordpfct.wpd.3xx
%System Root%\Documents and Settings\HELP_DECRYPT.TXT
%System Root%\Documents and Settings\HELP_DECRYPT.HTML
%System Root%\Documents and Settings\HELP_DECRYPT.URL
%System Root%\Documents and Settings\HELP_DECRYPT.PNG
%System Root%\HELP_DECRYPT.TXT
%System Root%\HELP_DECRYPT.HTML
%System Root%\HELP_DECRYPT.URL
%System Root%\HELP_DECRYPT.PNG
%Desktop%\HELP_DECRYPT.TXT
%Desktop%\HELP_DECRYPT.HTML
%Desktop%\HELP_DECRYPT.URL
%Desktop%\HELP_DECRYPT.PNG
Once located, select the file then press SHIFT+DELETE to delete it.
*Note: Read the following Microsoft page if these steps do not work on Windows 7 and Windows Server 2008 (R2).

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Trojan.Win32.CRYPTODEF.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 7

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.

%System Root%\cb8b48d

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Trojan.Win32.CRYPTODEF.A

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