Spyware is one of the most insidious forms of malware: It usually operates unnoticed in the background and specifically collects sensitive information. An infection can have serious consequences, especially for businesses—ranging from the theft of login credentials to industrial espionage. But how does spyware get onto a system, and how can you recognize it? In this article, you’ll learn how spyware works and what measures you can take to effectively protect your business.
What is spyware?
Spyware is a form of malicious software (malware) that is distributed with the aim of collecting information from an infected device and transmitting it to third parties, in most cases without the knowledge or consent of the affected person or organization.
The information that spyware can collect includes, among other things, login credentials, financial information, communication content, keystrokes, usage data, or confidential company documents. Attackers use this data, for example, for identity theft, industrial espionage, extortion attempts, or to prepare further cyberattacks.
While spyware long primarily affected private individuals, modern spyware is increasingly targeting businesses. There, access to trade secrets, customer data, or user accounts often promises significantly higher profits for criminals.
How does spyware work?
The exact range of functions varies from one piece of malware to another. However, the basic approach is usually similar.
First, the malware must gain access to a system. Attackers use various distribution methods to achieve this. In addition to compromised websites, manipulated software downloads, or exploited security vulnerabilities, email plays a particularly central role. Phishing messages with malicious attachments or links have been among the most successful methods for infiltrating malware into companies for years.
After infection, the spyware attempts to establish a permanent foothold on the system. It then begins the actual data collection. Depending on its capabilities, it logs keystrokes, reads files, takes screenshots, or monitors the user’s communications. The collected information is then transmitted by the attacker to systems under their control.
A particular problem is that spyware often causes no immediately visible damage. Unlike ransomware, it does not encrypt data or cripple systems. Rather, its goal is to remain undetected for as long as possible and to continuously siphon off information. It is precisely this stealthiness that makes spyware particularly dangerous for businesses, as an infection is often not noticed until data has already been leaked or further attacks have been carried out based on the information obtained.
As mentioned earlier, spyware can be distributed through various channels; however, email plays a particularly significant role in the corporate sector. Attackers use it to reach their targets directly and combine technical attacks with social engineering methods. Many successful spyware infections therefore begin with a phishing email designed to trick recipients into opening an attachment or clicking a link.
Why is spyware so dangerous for businesses?
The potential damage caused by spyware extends far beyond the theft of individual pieces of information. If login credentials fall into the hands of attackers, they can be used for further attacks or resold on the cybercrime black market. Confidential documents, customer data, or internal communications can be compromised, as can entire email accounts. Furthermore, spyware often serves as preparation for subsequent attacks. The information it gathers can be used, for example, for business email compromise attacks, targeted fraud attempts, or subsequent ransomware attacks. Added to this are potential violations of data protection and compliance requirements if personal or business-critical information falls into the wrong hands.
How can you recognize spyware?
Spyware is designed to operate as discreetly as possible. However, there are a few signs that may indicate an infection:
However, modern variants often cause barely noticeable symptoms. Companies should therefore not rely solely on manual detection, but rather implement technical safeguards that can identify suspicious behavior early on.
How can you protect yourself against spyware?
Effective protection consists of multiple layers of security. These include regular security updates, endpoint security solutions, raising employee awareness about phishing attacks, and monitoring suspicious network activity.
However, email deserves special attention. Many spyware campaigns begin with a seemingly harmless message designed to trick recipients into opening an attachment or clicking a link. Effectively securing this attack vector significantly reduces the risk of infection.
Protect Against Spyware with NoSpamProxy
Incoming emails are scanned during the SMTP communication process. Emails classified as suspicious are not moved to quarantine but are rejected before they are even accepted.
To detect malicious emails early and keep dangerous content out of users’ inboxes, NoSpamProxy offers a range of effective protection mechanisms:
NoSpamProxy Protection ATP
Despite modern filtering, analysis, and sandbox techniques, security solutions face a fundamental challenge: Not every threat is already known at the time an email is received. Cybercriminals are constantly refining their methods and often test new variants until they can circumvent existing detection methods.
With NoSpamProxy Protection ATP (Advanced Threat Protection), the existing protection concept is therefore expanded to include additional AI-powered analysis methods. The goal is to detect previously unknown threats early on and be able to respond to new findings, even if a message has already been delivered.
Traditional protection mechanisms detect many threats based on known signatures, characteristics, or behavioral patterns. Modern attacks, however, are increasingly customized or initially deployed in small-scale campaigns. As a result, they may still be unknown at the time they occur. This is precisely where ATP comes into play.
32Guards Recall
A key component of ATP is 32Guards Recall. This feature addresses a scenario that is becoming increasingly common in practice: An email initially appears unremarkable upon receipt, but is classified as malicious hours or days later based on new information. In such cases, Recall can send alerts to administrators, retain the original email in the clearing mailbox, and automatically remove messages that have already been delivered from the affected mailboxes. These actions can be configured individually. This provides companies with an additional layer of security that remains effective even after a message has been delivered.
32Guards DeepFile Analyzer
This protection is supplemented by the 32Guards DeepFile Analyzer. This technology scans attachments much more thoroughly than traditional signature-based methods. Among other things, it analyzes scripts, active content, and other suspicious characteristics that may indicate the presence of malware or spyware. This makes it possible to identify threats even if no known malware signature exists for them yet.
NoSpamProxy Protection ATP will be available starting in October 2026. With the release of NoSpamProxy Server 16.2, the ATP features are already fully available and can be used and tested free of charge and without restrictions until the official launch. Once the ATP license becomes available, a corresponding license will be required for continued use.
Conclusion
Spyware is one of the most dangerous types of malware because it often remains active and undetected for long periods of time. Unlike ransomware, it does not aim to cause visible damage or disrupt operations, but rather to secretly collect valuable information. As a result, companies often do not notice an attack until data has already been stolen, login credentials have been compromised, or further attacks are being prepared.
Email plays a particularly critical role in this context. Many spyware campaigns begin with a phishing message, a malicious attachment, or a malicious link. Securing email traffic should therefore be a central component of any security strategy.
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