World's biggest botnet sends 12.5 MILLION emails containing ransomware that could destroy your computer: Here's how to spot one
- Scarab malware is being sent out by Necurs, the largest email spam botnet ever
- Infected files are hidden in fake scanned documents that appear to be legitimate
- Once an attached 7zip is opened, malware takes over your computer and files
- A text file which then pops up threatens to erase them if the ransom isn't paid
Millions of computers are at risk of infection by a virulent spam attack that threatens to destroy your files, unless you pay a Bitcoin ransom.
The Scarab malware is being distributed by Necurs, the internet's largest email spam botnet, which has been used in a number of previous online onslaughts.
Within the first six hours of the attack 12.5 million emails had been distributed, with more than two million messages being sent out per hour at its height.
Scroll down for video
Millions of computers may have been infected by a virulent spam attack that threatens to destroy your files, unless you pay a Bitcoin ransom. The malware is being distributed by Necurs, the Internet's largest email spam botnet. This image shows an infected email
Security experts from anti-virus software company Forcepoint, based in Austin, Texas, were among the first to raise the alarm.
They found infected files were hidden in fake scanned documents which, according to the subject line of affected emails, were supposedly created using printers from a number of reputable firms.
This includes Lexmark, HP, Canon and Epson, giving the scam messages an appearance of legitimacy at first glance.
Once an attached 7zip is downloaded and opened, the malware takes over your computer and files, threatening to erase them if the ransom isn't paid.
Top domain countries targeted in the attack are the US, UK and Australia, followed by France and Germany.
Despite its wide distribution, Scarab is detected by most anti-malware software, which means you should receive a warning about the infected files.
Windows users unlucky enough to have been infected may be able to remove the malware by installing running anti-malware software in safe mode, although this is not guaranteed
Writing on the firm's blog, security researchers Ben Gibney and Roland Dela Paz said: 'The payload itself, Scarab, is a relatively new ransomware family that was discovered in June.
'Once installed it proceeds to encrypt files.
'A ransom note with the filename "If You Want To Get All Your Files Back, Please Read This.Txt" is dropped within each affected directory.
Once an attached 7zip is downloaded and opened, the malware takes over your computer and files, threatening to erase them if the ransom isn't paid. This image shows the ransom demand that appears after opening the attachment
Top domain countries targeted in the attack are the US, UK and Australia, followed by France and Germany. Despite its wide distribution, Scarab is detected by most anti-malware software, which means you should receive a warning about the infected files
'Unusually, the note does not specify the amount being demanded, instead simply stating that "the price depends on how fast you write to us".
'This note is also automatically opened by the malware after execution.'
A botnet is a collection of internet-connected devices, which may include PCs, servers, mobile devices and internet of things devices that are infected and controlled by a common type of malware.
Users are often unaware of a botnet infecting their system.
Once a botnet's owner is in control of your computer, they can use your machine in combination with others, over a network called a botnet, to carry out other nefarious tasks.
There are a number of common tasks executed by botnets.
This can include using your machine's power to assist in distributed denial-of-service (DDoS) attacks to shut down websites.
Ransomware is a type of malicious software that criminals use to attack computer systems. Hackers often demand the victim to pay ransom money to access their files or remove harmful programmes
Within the first six hours of the attack 12.5 million emails had been distributed, with more than two million emails being sent out per hour at its height. This graphic shows the number of Scarab emails intercepted per hour by Forcepoint
The can also be used to: email spam out to millions of internet users; generate fake Internet traffic on a third-party website for financial gain; replace banner ads in your web browser specifically targeted at you; enable pop-ups ads designed to get you to pay for the removal of the botnet through a fake anti-spyware package.
The biggest giveaway of a malware email is that they are sent without being asked for, so it is always best practice to never open an unsolicited attachment.
Archive files, like the 7zip format used in the attack, are also another warning sign of potentially dangerous content.
These types of file can be used to try and bypass detection by anti-virus scans.
Manually scanning suspicious emails with anti-virus and anti-malware software may also reveal any hidden infections, although this is not guaranteed - particularly if it has not been updated recently.
There may also be spelling mistakes or other grammatical errors in the subject line, email address or body text that give the game away.
Keeping a data backup either via the cloud or external storage device that is not always connected to your PC can help to protect your data.
Most watched News videos
- Octopus outsmarts predator in a way the world has never seen
- Devastation at Cocoanut Grove after deadly fire in 1942
- Horrifying moment rescuers find dog cruelly encased in ice by owner
- 'Drugged-up' store clerks appear to fall asleep at the register
- Thieves steal car in Solihull without even using owners keys
- Amazing drone vision shows shark swimming between surfers
- Shocking video of three vehicle crash but everyone walks away!
- Shocking moment two commuters have sex at Melbourne train station
- Prince Harry and Meghan Markle announce their engagement
- Intense Black Friday fight in Kmart leaves man with shattered hip
- Prince Harry and Meghan Markle's tender moments during engagement
- Working mother Sandra shows off her abs after 12 week course
- Fascinating images of 20th century socialite who spent...
- Mobster acquitted of masterminding the infamous 1978...
- Oi, you got any spare anti-freeze in there? Curious polar...
- That's awkward! Leopard stalking its prey is forced to...
- Now THAT'S a thigh gap! Woman gets her leg stuck in a...
- Reindeer bloodbath! Horror as 106 of the beasts are run...
- A not-so Happy Meal: Adorable moment two-year-old dumps...
- North Korea is more likely to launch a nuclear weapon...
- Rocket launch falls flat! 'Mad scientist' forced to...
- 'What’s the f***ing point?' John McCain tells Hillary...
- Dog named Picasso because of his unusual looks FINALLY...
- 'We meet at Christmas in New York...soon': ISIS post...
- 'The Crusaders' feast is approaching - show them the...
- My crazy round of golf with the World No. 1, Tiger Woods...
- Banking heir, 52, spends $3m turning his 275-acre New...
- Indiana nurse sparks fury after tweeting that 'white...
- Horrifying moment circus tiger breaks out of its cage in...
- Ouch! Israeli police accidentally knock over unsuspecting...