There are many types of malicious software (malware) out there, and worm malware is in a class of its own. To understand why worms are so dangerous and how they differ from ordinary computer viruses, we need to begin with a worm malware definition.
Worm malware is a form of malicious software that spreads through computer networks independently by exploiting network protocol or operating system vulnerabilities.
Simple though this definition may sound, it opens a metaphorical can of worms in just a few words. You may have thought that viruses were your greatest foe, but worms are far worse.
The main difference between worms and viruses is that viruses embed themselves in programmes. They can’t spread independently. Worms, on the other hand, are independent pieces of software. They burrow into networks without any “help” from users, replicating and spreading. Once they’ve thoroughly infiltrated their targets, the real attack begins.
Anatomy of an Attack: How Does Worm Malware Work?
1. The Worm is Introduced
Worms can spread through human agency. For example, you might open an infected emailed attachment, visit a malicious website, download a file with a hidden worm, or connect an infected external device. But oftentimes, worms find a way into a computer without you doing anything at all. They exploit a network or operating system vulnerability. You haven’t opened anything, plugged anything in, or downloaded anything, but your device is infected.
2. The Worm Replicates Itself
Once it has arrived, the worm gets busy. It looks around for other vulnerable devices and systems, and once it has spotted a potential target, it works to exploit its vulnerabilities. For example, unpatched software or weak authentications open a path for worms, and they rapidly take advantage of these weaknesses.
3. The Worm Spreads From The Newly-Infected Systems
Having spread from its initial source, the worm keeps repeating the process. It instals itself, and starts looking for more targets. The term “exponential spread” is no exaggeration when applied to worms.
4. The Worm Delivers its Payload – or Waits
Some worms automatically deliver a payload. Others wait for instructions from a command and control server. Payload delivery comes in many forms. It could mean that files are deleted, sensitive information is stolen, or that backdoors for remote access are opened. The affected system can be hijacked into sending out other malware or be used to launch denial of service attacks.
5. Evading Detection
Some worms are able to cover their tracks. For example, they can hide the evidence of what they’ve been doing by deleting logs. With users being unaware that their devices are being used for nefarious purposes, the worm is able to do more damage for longer.
Worm Malware at Work: Examples
In 2010, a computer worm known as Stuxnet hit world headlines, showing how worm malware can be used to wage cyberwarfare. It targeted Iran’s nuclear program and was directly responsible for the destruction of nuclear centrifuges after targeting industrial control systems. It was the first time that a cyber security threat caused physical damage on such a scale, and its ability to remain undetected allowed it to wreak havoc.
Worm malware continues to pose a significant and much more generalised threat. Raspberry Robin, first detected in 2021, is still making cyber security headlines in 2024. Its routes of spread have developed over time, and its ability to hide itself and escape analysis shows a high level of sophistication. Once a device is infected, the worm uses the anonymised Tor network to communicate with command and control servers.
Microsoft has identified Raspberry Robin as one of the largest platforms for malware distribution. Although it initially targeted tech and manufacturing businesses, it has expanded beyond these industries and has been linked to multi-stage intrusions requiring access to highly privileged credentials.
Symptoms of Worm Malware Infections
Symptoms of a worm infection vary, but there are some common symptoms to look out for. These include:
- Increases in network traffic during off-peak hours
- Spikes in data transmission with no apparent cause
- Unauthorised network activity
- Slowed-down access to network resources and sluggish internet performance
- System crashes and freezes
- Programmes that close or open unexpectedly
- Unknown processes consuming CPU resources
- Files or programmes appearing on systems without user intervention
- Emails or messages sent from devices without users’ knowledge
- Unauthorised alteration of features such as firewall rules
- Altered browser settings
- Increased pop-ups and ads during browsing
- Activity is triggered on idle systems
- Disabled or un-updatable security features
What to Do if You Suspect a Worm Infection
Some worms use sophisticated strategies to evade detection. For example, Raspberry Robin attempts to confuse cybersecurity experts by dropping a fake payload when devices are being analysed in sandbox mode.
If you suspect that even one device in your network is affected by a worm, you should get expert help immediately. Worms spread rapidly and may have affected your entire network by the time you spot any symptoms.
Meanwhile, you should disconnect devices from your network and disable internet access to block hackers’ command and control system access. Alert your organisation to the symptoms you’ve noticed and collect evidence to help with diagnosis and mitigation.
Cybersecurity professionals will seek to identify the worm and the vulnerabilities that allowed the infection to occur. For example, operating systems and software that require updates may have led to the infection, so simply removing the malware isn’t enough to protect you. If the infection is widespread, it may be necessary to restore data from a clean backup.
Once you’re back up and running, it will be important to monitor your network for activity that may indicate re-infection or the presence of residual malware.
Stay Safe With Advantex
Cybercriminals are constantly seeking out vulnerabilities that can allow them access to your business-critical networks, systems, and data. The risks are great and the consequences range from theft and fraud to physical sabotage.
Avantex works with your IT team or, if needed, as your IT team to keep your systems running smoothly and protect your business from cyberattacks. Find out about our cyber security services today. Enjoy peace of mind tomorrow.
