Spooling is a lesser-used phrase to identify a potential DoS (Denial of Service) or DDoS attack. As an abbreviation for “Simultaneous Peripheral Operation On-line”, a spool attack can often overload a system and cause it to crash, or leak – depending on the system and circumstances.
Today, we’re going to venture into what spooling is – and how you can identify and mitigate it as a cybersecurity professional.
What is Spooling?
Spooling is a buffering process between two devices. When a device enters a spooling state, it is simply sending or receiving information from one device to another, and ensuring the data is readable for the receiving device. An easy and common example of this would be a printer and PC. The PC has a document, and it sends that to the printer.
The printer can’t display it as a .doc format. In this case, a spooling process happens where the data is transmitted, and transformed between the device so the printer can use the information to print it. The same goes for a DoS attack – where data is being transmitted, in an incorrect format at a rapid pace causing the receiving system to fail, or be overloaded.
What does Spool stand for?
Spool (or spooling) stands for “Simultaneous Peripheral Operations Online”. Whilst this is a bit of a tongue twister, there is an easier way of understanding this. Similarly to how you may type on a keyboard, or send a text message – there is an instantaneous action for whatever you do.
An example which is commonly used is when you press “Print” on your system. The systems are communicating to one another to ensure the data is handed over correctly, and in a readable format (for the system). This is the same for any system that communicates with another.
What is Spooling in Cybersecurity?
Whilst we’ve looked at spooling in normal systems, how does this affect or work in the cybersecurity world? The same goes for a DoS attack – where data is being transmitted, in an incorrect format at a rapid pace causing the receiving system to fail, or be overloaded.
How can an attacker use a Spooling Attack?
An attacker may opt to use a spooling attack in a number of different ways, usually to improve their persistence within a system, device, or organization. A spooling attack may be used.
- Exposing, finding, or exploiting vulnerabilities and weaknesses within a network.
- Sending through Malicious Payloads
- Sending some kind of Executable (could literally be a PDF or a printed document).
- Gain persistence – a common term for remaining within a system, or opening up more doors to access a system.
- Privilege Escalation – to gain extra permissions or create accounts/systems that are able to do more than the initial attack.
How you can prevent a Spooling Attack?
Because of what spooling does, it’s critical to most computer systems and disabling all spooling services will actually just cause you more problems in the long run. To prevent a spooling attack, you would follow the typical DoS remediation steps like below.
Firewalls & Network Strengthening
Whilst you may not be able to protect the devices themselves from operating or running the spooling commands in question, you may be able to strengthen your network to prevent people from the outside from abusing it. Firewalls can come in many forms, but by using either an endpoint firewall (such as Microsoft Defender) or a physical/virtual firewall unit on the outside, known as a perimeter firewall, will help you massively.
Whilst spooling does what it wants, when it wants, rate limiting might not be the strongest approach but can prevent command spamming which may lead to a spooling attack. Again, specifics on how you would do this vary massively from system to system, environment to environment – but this is another possibility.
DoS/DDoS Protection Services
DoS and DDoS protection services are cropping up on the internet quite frequently now, so much so that these services could help you prevent a spooling attack. Some service providers will actually provide this straight-up as a feature – so make sure to look into that should you be wanting to go down that route.
Regular Patching & Updating
As with any type of security issue or attack, having up-to-date systems and devices will help you stay ahead of any cyber criminals. These types of patches and updates, whilst potentially long-winded will help patch any flaws or vulnerabilities within a system that may be exploited by an attacker, should they find a way to expose it.
Overall, whilst spooling attacks are not super common or referred to as just standard DoS attacks, these are still seen worldwide daily. This type of attack, whilst uncommon, is still one you should protect yourself against to stay ahead of cybercriminals. If you’ve had a spooling attack – you may need to let the authorities know, such as the NCSC.