Null mumbai Session on ransomware by_Aditya Jamkhande

Name : Aditya Jamkhande

Current Organization : Tata Consultancy Services

Position : Senior Security Analyst

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by_Aditya_Jamkhande

Few Basics (a short video on

Bitcoin)

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What is a Ransomware

a type of malicious software designed to block access to a computer system

until a sum of money is paid

Ransomware is a type of malware that can be covertly installed on a

computer without knowledge or intention of the user that restricts access to

the infected computer system in some way, and demands that the user pay

a ransom to the malware operators to remove the restriction.

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History The first known Ransomware was the 1989 “AIDS” Trojan (also

known as “PC Cyborg”) written by Joseph Popp

Extortionate ransomware became prominent in May 2005

By mid-2006, worms such as Gpcode, TROJ.RANSOM.A,

Archiveus, Cryzip and MayArchive began utilizing more

sophasticated RSA encryption schemes, with ever-increasing Key-

sizes

In 2011,a ransomware worm imitating the windows product

activation notice surfaced

In February 2013, a ransomware worm based off the Stamp.Ek

exploit kit surfaced

In July 2013, an OS X-specific ransomware worm came into action

Cryptolocker has raked in around 5 million dollars and still counting

since the end of 2013


Terminology and Propagation

The cryptovirology form of the attack has ransomware systematically

encrypt files on the system's hard drive, which becomes intractable to

decrypt without paying the ransom for the decryption key.

(Cryptovirology is a field that studies how to use cryptography to design

powerful malicious software.)

Other attacks may simply lock the system and display messages intended

to coax the user into paying.

Ransomware typically propagates as a Trojan, whose payload is disguised

as a seemingly legitimate file.


How Cyber criminals / Hackers install

ransomware?

Ransomware generates a pop-up window, webpage or email

warning from what looks like an official authority

Ransomware is usually installed when you open

- A malicious email attachment

- Click a malicious link in

1. an email message

2. an instant message

3. on social networking site

Ransomware can even be installed when you visit a

malicious site


Types of Ransomware

Encryption Ransomware

Lock Screen Ransomware

Master Boot Record (MBR) Ransomware


Encryption Ransomware

Encrypts personal files/folders (e.g., the contents of you‟re my documents folder-documents, spreadsheets, pictures, videos)

Files are deleted once they are encrypted and generally there is a text file in the same folder as the now-inaccessible files with instructions for payment.

You may see a lock screen but not all variants show one

Instead you may only notice a problem when you attempt to open your files

This type is also called „file encryptor‟ ransomware


Lock Screen Ransomware

„Locks‟ the screen and demands payment

Presents a full screen image that blocks all the

other windows

This type is called „WinLocker‟ ransomware

No personal files are encrypted


Master Boot Record (MBR)

Ransomware

The master boot record (MBR) is a section of the

computer‟s hard drive that allows the operating system to

boot up

MBR ransomware changes the computer‟s MBR so the

normal boot process is interrupted

A ransom demand is displayed on screen instead


Reveton

In 2012, a major ransomware worm known as Reveton began to spread.

It is also known as "police trojan".

Its payload displays a warning purportedly from a law enforcement agency.

claiming that the computer had been used for illegal activities, such as

downloading pirated software, promoting terrorism, copyright etc.

The warning informs the user that to unlock their system they would have to pay

a fine.

To increase the illusion that the computer is being tracked by law enforcement,

the screen also displays the computer's IP address and footage from a

computer's webcam.


CryptoLocker

An Encrypting ransomware reappeared in 2013.

Distributed either as an attachment to a malicious e-mail or as a drive-by download.

encrypts certain types of files stored on local and mounted network drives using RSA public-key cryptography.

The private key stored only on the malware's control servers.

Offers to decrypt the data if a payment (through either Bitcoin or a pre-paid voucher) is made by a stated deadline.

threatens to delete the private key if the deadline passes.

If the deadline is not met, the malware offers to decrypt data via an online service provided by the malware's operators, for a significantly higher price in Bitcoin.


How to prevent ransomware ?

Keep all of the software on your computer up to date.

Make sure automatic updating is turned on to get all the latest Microsoft security updates and browser-related components (Java, Adobe, and the like).

Keep your firewall turned on.

Don't open spam email messages or click links on suspicious websites. (CryptoLocker spreads via .zip files sent as email attachments, for example.)


Cont..

Download Microsoft Security Essentials, which is free, or use another reputable antivirus and anti-malware program.

If you run Windows 8 or Windows RT, you don‟t need Microsoft Security Essentials.

Scan your computer with the Microsoft Safety Scanner.

Keep your browser clean.

Always have a good backup system in place, just in case your PC does become infected and you can‟t recover your files.


Identify The Ransomware

Most commonly, ransomware is saved to one of

the following locations:

C:\Programdata\(random alpha numerics).exe

C:\Users\(username)\0.(random numbers).exe

C:\Users\Username\AppData\(random alpha

numerics).exe


Removal – Microsoft Procedure

The following Microsoft products can detect and remove this threat:

Windows Defender (built into Windows 8)

Microsoft Security Essentials

Microsoft Safety Scanner

Windows Defender Offline (Some ransomware will not allow you to use the products listed here, so you might have to start your computer from a Windows Defender Offline disk.)


Removal – Other Anti-Malware

Programs

Start your computer in “Safe Mode with Networking”.

Stop and clean malicious running processes.

○ Download and save "RogueKiller" utility on your computer'*

(e.g. your Desktop).

○ Double Click to run RogueKiller.

○ Let the prescan to complete and then press on "Scan" button

to perform a full scan.

○ When the full scan is completed, press the "Delete" button to

remove all malicious items found.

○ Close RogueKiller and proceed to the next Step.


Clean Remaining Malicious Threats

Download and install a reliable FREE/Pro anti malware programs to clean your computer from remaining malicious threats. E.g. Malwarebytes Anti-Malware, Norton etc.

Run "Anti-Malware" and allow the program to update to it's latest version and malicious database if needed.

let the program scan your system for threats.

Select all threats in result scan and remove all.

When the removal of infected objects process is complete,

“Restart your system to remove all active threats properly”.


Delete Cryptolocker Hidden Files

Enable the hidden files view from control panel.

Navigate to the following paths and delete all Cryptolocker Hidden files:

For Windows XP

C:\Documents and Settings\<YOUR USERNAME>\Application Data\RandomFileName.exe

e.g. {DAEB88E5-FA8E-E0D1-8FCD-BFC7D2F6ED25}.exe

C:\WINDOWS\system32\msctfime.ime

For Windows Vista or Windows 7 C:\Users\<YOUR USERNAME>\AppData\Roaming\RandomFileName.exe

e.g. {DAEB88E5-FA8E-E0D1-8FCD-BFC7D2F6ED25}.exe

C:\WINDOWS\system32\msctfime.ime


Delete Temporary files

Finally delete all files and folders under your TEMP folders:

For Windows Vista or Windows 7

C:\Users\<YOUR USERNAME>\AppData\Local\Temp\

C:\Windows\Temp\

For Windows XP C:\Documents and Settings\<YOUR USERNAME>\Local

Settings\Temp\

C:\Windows\Temp\


File Restore- Shadow Copies

Navigate to the folder or the file that you want to restore in a previous state and right-click on it.

From the drop-down menu select “Restore Previous Versions”. *

Notice* for Windows XP users: Select “Properties” and then the “Previous Versions” tab.

Then choose a particular version of folder or file and the press the: “Open” button to view the contents of that folder/file.

“Copy” to copy this folder/file to another location on your computer (e.g. you external hard drive).

“Restore” to restore the folder file to the same location and replace the existing one.


Removing Reveton

Name- Trojan:W32/Reveton and Trojan:W32/Urausy

Boot the system into 'Safe Mode with Command Prompt.'

In the command prompt, type "regedit" and press Enter.

Look for the following registry values and remove them.

For Reveton, delete the "ctfmon.exe" registry value from

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run


For Urausy, delete the "shell" registry value from

HKEY_CURRENT_USER\Software\Microsoft\WindowsNT\CurrentVersion\Winlogon

ONLY IF these two conditions are met:

1. The "shell" registry value is located under HKEY_CURRENT_USER

and Not “ HKEY_LOCAL_MACHINE”. WARNING! Deleting the "shell" value if it is listed under HKEY_LOCAL_MACHINE may break the Windows system.

2. There is a reference to a .dat file (e.g. skype.dat) in the value data.

Reboot the system again, this time into Normal mode.

Finally, run a full computer scan to repair any remaining

files.


Defensive Measures

Backup and Recovery

Patch Regiment

Follow the principle of Least Privilege

(People / Software / Network)


Conclusion

When it comes to malware attacks, knowledge is the best possible weapon to prevent them. Be careful what you click!! Preventive measures should be taken before ransomwares establish strong hold. Keeping all the software updated and getting latest security updates might help to prevent the attacks. Use of antivirus and original software is highly recommended. Creating software restriction policy is the best tool to prevent a Cryptolocker infection in the first place in networks.


References

http://www.microsoft.com/security/resources/ransomware-whatis.aspx

http://www.microsoft.com/security/portal/mmpc/shared/ransomware.aspx

http://www.sophos.com/en-us/support/knowledgebase/119006.aspx

http://us.norton.com/ransomware

http://en.wikipedia.org/wiki/Ransomware

For details in removal and recovery solutions visit:

http://www.wintips.org/how-to-remove-cryptolocker-ransomware-and-restore-your-files/

http://www.f-secure.com/en/web/labs_global/removal/removing-ransomware

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http://us.norton.com/ransomware

http://en.wikipedia.org/wiki/Ransomware























Null mumbai Session on ransomware by_Aditya Jamkhande

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