Ransomware

WHAT IS RANSOMWARE?

A Reveton payload attempting to extort money from a user, by fraudulently claiming that the user must pay a fine to the Metropolitan Police Service.

Ransomware is a type of malware that infects a computer and restricts a user’s access to the infected computer. This type of malware, attempts to extort money from victims by displaying an on-screen alert. These alerts often state that their computer has been locked or that all of their files have been encrypted, and demand that a ransom is paid to restore access.

Ransomware is typically spread through phishing emails that contain malicious attachments and drive-by downloading. Drive-by downloading occurs when a user unknowingly visits an infected website and malware is downloaded and installed without their knowledge. Crypto ransomware, a variant that encrypts files, is typically spread through similar methods, and has been spread through Web-based instant messaging applications.

WHY IS IT SO EFFECTIVE?

Ransomware payloads utilize elements of scareware to extort money from the system’s user. The payload may, for example, display notices purportedly issued by companies or law enforcement agencies which falsely claim that the system had been used for illegal activities, or contains illegal content such as pornography and pirated software or media.

Some ransomware payloads imitate Windows XP’s product activation notices, falsely claiming that their computer’s Windows installation is counterfeit or requires re-activation. These tactics coax the user into paying the malware’s author to remove the ransomware, either by supplying a program which can decrypt the files, or by sending an unlock code that undoes the changes the payload has made. These payments are often delivered using either a wire transfer, premium-rate text messages, through an online payment voucher service such as Ukash or Paysafecard, or most recently, the digital currency Bitcoin.

 CryptoLocker needs to be taken very seriously, because it can result in the total and irreversible destruction of all your personal and company files.

Examples of Scareware messages related to ransomware:

“Your computer has been infected with a virus. Click here to resolve the issue.”
“All files on your computer have been encrypted. You must pay this ransom within 72 hours to regain access to your data.”
“Your computer was used to visit websites with illegal content. To unlock your computer, you must pay a $100 fine.”

VARIANTS

Here’s a Excel document that had been specifically encrypted by CryptoLocker

This financial success has likely led to a proliferation of ransomware variants. In 2013, more destructive and lucrative ransomware variants were introduced including Xorist, CryptorBit, and CryptoLocker. Some variants encrypt not just the files on the infected device but also the contents of shared or networked drives. These variants are considered destructive because they encrypt user’s and organization’s files, and render them useless until criminals receive a ransom.

Additional variants observed in 2014 included CryptoDefense and Cryptowall, which are also considered destructive. Reports indicate that CryptoDefense and Cryptowall share the same code, and that only the name of malware itself is different. Similar to CryptoLocker, these variants also encrypt files on the local computer, shared network files, and removable media.

INTERCONNECTION  TYPES OF MALWARE

Systems infected with ransomware are also often infected with other malware. In the case of CryptoLocker, a user typically becomes infected by opening a malicious attachment from an email. This malicious attachment contains Upatre, a downloader, which infects the user with GameOver Zeus. GameOver Zeus is a variant of the Zeus Trojan that steals banking information and is also used to steal other types of data. Once a system is infected with GameOver Zeus, Upatre will also download CryptoLocker. Finally, CryptoLocker encrypts files on the infected system, and requests that a ransom be paid.

The close ties between ransomware and other types of malware were demonstrated through the recent botnet disruption operation against GameOver Zeus, which also proved effective against CryptoLocker.

Ransomware doesn’t choose targets. Both home users and businesses can become infected with ransomware whith negative consequences, including:

Temporary or permanent loss of sensitive or proprietary information;

Disruption to regular operations;

Financial losses incurred to restore systems and files;

Potential harm to an organization’s reputation.

Paying the ransom is not a guarantee that the encrypted files will be released, but  it only guarantees that the malicious actors receive the victim’s money and their banking information. In addition, decrypting files does not mean the malware infection itself has been removed.

Prevention

Infections can be devastating to an individual or organization, and recovery can be a difficult process that may require Data Recovery services.

Recommended preventive measures to protect computers and networks from ransomware infections:

Do not follow unsolicited web links in email.

Use caution when opening email attachments.

Follow safe practices when browsing the web.

Perform regular backups of all critical information to limit the impact of data loss and to help the recovery process. This data should be kept on a separate device, and backups should be stored offline.

Maintain up-to-date anti-virus software.

Keep your operating system and software up-to-date with the latest patches.

As with other forms of malware, security software might not detect a ransomware payload, or, especially in the case of encrypting payloads, only after encryption is underway or complete, particularly if a new version unknown to the protective software is distributed.

If an attack is suspected or detected in its early stages, it takes some time for encryption to take place; immediate removal of the malware (a relatively simple process) before it has completed would limit its damage to data. Security experts have suggested precautionary measures for dealing with ransomware, such as using software or other security policies to block known payloads from launching, along with “offline” backups of data stored in locations inaccessible to the malware.

One of the most powerfull software package that is available to help against ransomware is the well known Malwarebytes Anti-Malware and recommended for prevention and removal from all types of Malware.

Ransomware