What researchers believe to be a variant of the notorious HDDCryptor malware family has hit the Muni subway system of San Francisco. The hack resulted in over 2,000 systems to become compromised and their hard drives to be encrypted. The ransomware displayed a short message on boot screen, linking to the e-mail firstname.lastname@example.org. Then, the cyber-criminals demanded over 73 thousand dollars to be paid as a ransom to restore access to the systems on the subway. This is yet another case of how IoT (Internet of Things) can impact our daily lives.
|Short Description||The malware encrypts the hard drive of the user with a custom password, denying all access to it. It asks for 100 BTC ransom payment to send a password for encryption.|
|Symptoms||On system boot displays the following ransom note – “You Hacked, ALL Data Encrypted, Contact For Key (email@example.com) ID:”|
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|User Experience||Join our forum to Discuss Cryptom Ransomware.|
The Cryptom Ransomware Attacked Different Systems
Not only systems within the Municipal Transport Agency of San Francisco’s subway were infected. The ransomware managed to impact many other related systems as well, such as administrative computers, systems for payment, SQL database computers, terminals and kiosks. The malware has most likely been coded by someone with experience because it had a worm-like capability to spread across different types of devices, suggesting the sophistication behind it. Not only this but other computers, even including Macs and other PC’s were also hit, rising the number of infected devices to roughly 8,500.
What Does Cryptom Ransowmare Do
The goal of Cryptom is to generate profit at the user’s expense. The attack by the virus may portray a worm-like behavior, which means it spreads from an infected device to an infected device, raising some serious security issues in various IoT devices.
After infecting a given machine, the ransomware does not just encrypt the files on the compromised device. Instead, it focuses on performing various tasks oriented with attacking the MBR (Master Boot Record) which if overridden, allows it to directly encrypt the SSD or HDD on the compromised device.
After this encryption process is complete, the ransomware generates a unique unlock key via it’s encryption mechanism which will allow for the successful deciphering of the encrypted data. And Cryptom finally generates a boot message saying the drive is encrypted:
The Origins of HDDCryptor
Similar to other HDDCryptor variant, Mamba Ransomware, Cryptom may exhibit the same behavior. The sole idea for this specific file encryption malware is using coding skills to generate a sophisticated ransomware virus by taking the source code from open source program, known as DiskCryptor which is originally used for protection of hard drives.
It is believed that not only the ransomware creates multiple files on the main logical drive of the infected computer, but it also uses those files to obtain administrative privileges. This is used most likely for Cryptom to create a new user on the compromised device and then most likely use the following ciphers to encrypt the hard drive:
- AES-512 encryption algorithm
- XTS encryption mode
What is The Impact
Thousands of devices in the SF subway and bus network were rebooted with the ransom message on them. Upon contacting the e-mail address the cyber-criminals responded that their software infects automatically and they did not expect any ransom to be paid. But either way they demanded the insane ransom amount of approximately 100 BTC for the payoff.
The impact of this infection is that the SF public transport organization was pushed into opening the gates for access to the subway, allowing everyone to ride for free.
Cryptom Ransomware – Predictions, Protection and Removal
Given in consideration that cities, like San Francisco’s transport system is interconnected, this is what allowed for the Cryptom virus to spread so quickly. Even the cyber-criminals have admitted that this was not their initial target. However, we could be seeing more and more ransomware attacks on interconnected devices impacting our daily life, like ATM’s, security cameras, parking meters and every other device with an OS and a screen belonging to the same network.
In case you have been infected by this ransomware virus, we urge you to be extremely careful in what you are doing. HDD encryptors have been around for quite some time and viruses, like “Petya” and “Mischa” have proven that they work. As soon as you see the ransom note, the first step we advise you to take is to unplug your HDD from the device immediately. To learn how to do this, you can follow our instructions (step 1 to step 3 in the “Decryption Phase”) in the article below:
After extracting the hard drive, it is recommended to not tamper with it in any way and wait until malware researchers come up with a solution, immediately after which we will update this article with a web link to the solution itself.
In the mean-time the best thing you can do to increase protection is to make a system consisting of protection tools and a security oriented behavior. Here is what we suggest you to do:
1. Read our ransomware protection tips.
2. Read our research on how to safely store your files to protect them from ransomware viruses in general.
3. Download an advanced anti-malware tool that will help increase general malware and exploit protection:
4. Download the Talos’s tool which aims to protect the MBR from ransomwareand other viruses.