Ransomware |


CompTIA Sec+ Objectives 1.1

Ransomware is a type of malicious software that infects a computer and restricts users’ access to it until a ransom is paid to unlock it. Ransomware variants have been observed for several years and often attempt to extort money from victims by displaying an on-screen alert. Typically, these alerts state that the user’s systems have been locked or that the user’s files have been encrypted. Users are told that unless a ransom is paid, access will not be restored.


How does a computer become infected with Ransomware?

Ransomware (and other malware) is very often spread via email (phishing). Targeting is very straightforward using email as an attack vector since a domain name is a great identifier. The hacker then makes it clear that the information is stolen and offers to give that information back if the victim pays a ransom.
Victims are often asked to pay the ransom in the form of Bitcoins. If the ransom is paid, the cybercriminals may unlock the data or send a key to for the encrypted files.

Drive-by downloading occurs when a user unknowingly visits an infected website and then malware is downloaded and installed without the user’s knowledge.

Crypto ransomware, a malware variant that encrypts files, is spread through similar methods and has also been spread through social media, such as Web-based instant messaging applications. Additionally, newer methods of ransomware infection have been observed. For example, vulnerable Web servers have been exploited as an entry point to gain access to an organization’s network.

Why is Ransomware so effective?

The authors of ransomware instill fear and panic into their victims, causing them to click on a link or pay a ransom, and users systems can become infected with additional malware. Ransomware displays intimidating messages similar to those below:

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

Why is Ransomware spreading?

Ransomware attacks and their variants are rapidly evolving to counter preventive technologies for several reasons:

  • 1) Easy availability of malware kits that can be used to create new malware samples on demand
  • 2) Use of known good generic interpreters to create cross-platform ransomware (e.g., Ransom32 uses Node.js with a JavaScript payload)
  • 3) Use of new techniques, such as encrypting the complete disk instead of selected files

Additionally, today’s thieves don’t even have to be tech savvy. Ransomware marketplaces have sprouted up online, offering malware strains for any would-be cybercrook and generating extra profit for the malware authors, who often ask for a cut in the ransom proceeds.

Examples of Ransomware attacks​


CryptoLocker Ransomware Attack

CyptoLocker botnet is one of the oldest forms of cyber attacks which has been around for the past two decades. The CyptoLocker ransomware came into existence in 2013 when hackers used the original CryptoLocker botnet approach in ransomware.

CyptoLocker ransomware is the most destructive form of ransomware since it uses strong encryption algorithms. It is often impossible to decrypt (restore) the Crypto ransomware-infected computer and files without paying the ransom.

WannaCry Ransomware Attack 

WannaCry is the most widely known ransomware variant across the globe. The WannaCry ransomware attack has affected nearly 125,000 organizations in over 150 countries. Some of the alternative names given to the WannaCry ransomware are WCry or WanaCrypt0r.

Cerber Ransomware Attack

Cerber ransomware attacks targeted cloud-based Office 365 users. Millions of Office 365 users have fallen prey to an elaborate phishing campaign carried out by the Cerber ransomware

CryptoWall Ransomware Attack

CryptoWall is an advanced form of CryptoLocker ransomware. It came into existence since early 2014 after the downfall of the original CryptoLocker variant. Today, there are multiple variants of CryptoWall in existence. It includes CryptoDefense, CryptoBit, CryptoWall 2.0, and CryptoWall 3.0.

Locky Ransomware Attack

Locky is another ransomware variant which is designed to lock the victim’s computer and prevent them from using it until a ransom is paid. It usually spread through a seemingly benign email message disguised as an invoice.

GoldenEye Ransomware Attack

GoldenEye is similar to the infamous Petya ransomware. It spreads through a massive social engineering campaign that targets human resources departments. When a user downloads a GoldenEye-infected file, it silently launches a macro which encrypts files on the victim’s computer.

Jigsaw Ransomware Attack

Jigsaw is one of the most destructive types of ransomware attacks, because it encrypts and progressively deletes the encrypted files until a ransom is paid. It starts deleting the files one after the other on an hourly basis until the 72-hour mark- when all the remaining files are deleted.

When a user opens the email attachment, the invoice gets deleted automatically, and the victim is directed to enable macros to read the document. When the victim enables macros, it begins encrypting multiple file types using AES encryption.

Apart from the list of ransomware mentioned above, Petya, NotPetya, TeslaCrypt, TorrentLocker, ZCryptor, etc., are some of the other ransomware variants that are well-known for their malicious activities.


How to defend against ransomware?

Infections can be devastating to an individual or organization, and recovery can be a difficult process that may require the services of a reputable data recovery specialist.

US-CERT recommends that users and administrators take the following preventive measures to protect their computer networks from ransomware infection:

1) Employ a data backup and recovery plan for all critical information. Perform and test regular backups to limit the impact of data or system loss and to expedite the recovery process. Note that network-connected backups can also be affected by ransomware; critical backups should be isolated from the network for optimum protection.

2) Keep your operating system and software up-to-date with the latest patches. Vulnerable applications and operating systems are the targets of most attacks. Ensuring these are patched with the latest updates greatly reduces the number of exploitable entry points available to an attacker.

3) Maintain up-to-date anti-virus software, and scan all software downloaded from the internet prior to executing.

4) Restrict users’ ability (permissions) to install and run unwanted software applications, and apply the principle of “Least Privilege” to all systems and services. Restricting these privileges may prevent malware from running or limit its capability to spread through the network.

5) Avoid enabling macros from email attachments. If a user opens the attachment and enables macros, embedded code will execute the malware on the machine.

6) Do not follow unsolicited Web links in emails. Refer to the Phishing resources found on this website for more information.

I’m A Ransomware Victim What should I do?

Keep in mind that paying a ransom is no guarantee of receiving a decryption key.

“ASM advises that you never pay a ransom”

If you or your company have been a victim of ransomware you should report it immediately to CISA at www.us-cert.gov/report, a local FBI Field Office, or Secret Service Field Office.

Another good source of information if you have been a victim of ransomware and help you on unlocking some ransomware threats is to visit No More Ransom. If your device gets held for ransom, start by researching what type of ransomware it is. Then check out No More Ransom’s decryption tools and see if one is available for your ransomware.

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