Infostealer attacks: How hackers steal data from companies

Infostealer malware compromises millions of devices each year, exposing individuals' sensitive data. It's one of the most dangerous cybersecurity threats today, and enterprises usually fall victim to these attacks because of employee error, which can lead to devastating data breaches. If you want to safeguard your organization, it's essential to understand how these attacks exploit user mistakes and what steps you can take to protect the company's systems and data.

What are infostealers, and how do they work? 

Infostealers are malicious software designed to infiltrate computers and steal sensitive data. They can grab confidential information, including login credentials, passwords, credit card details, emails, cookies, photos, API tokens, browsing histories, and other files.

Infostealers compile all stolen information into a stealer log - a file containing a detailed record of the victim's sensitive data. Cybercriminals distribute these logs on the dark web, on underground forums and marketplaces, where other bad actors can download and use them. 

Infostealer attacks result in data leaks that can damage your company's reputation and cause financial loss. They can also inject malware and shut down daily operations. Furthermore, infostealers are often just a stepping stone to deploy a more damaging attack. Bad actors can use the stolen data for ransomware or insider training if, for example, they can grab documents with confidential information about financial transactions, mergers, or acquisitions.

Additionally, infostealer attacks on enterprises expose their clients to further threats. Stolen personal information helps hackers engage in numerous criminal activities, such as identity theft, account takeovers, and business email compromise, which can result in significant financial losses. 

How employees fall victim to infostealer attacks

Employees are the main gateway for infostealer attacks on enterprises. Once employees' devices have been compromised by infostealer malware, bad actors can use the stolen information to gain access and infiltrate corporate networks. User mistakes that lead to downloading infostealer malware include:

1. Interacting with phishing emails. Infostealers are most commonly spread through emails containing malicious attachments or links that lead to malware downloads. Phishing emails are disguised as legitimate communication, often impersonating trusted authorities. These types of emails can be mass-distributed or targeted (spear-phishing). Bad actors can execute targeted attacks using private user information that was previously leaked on the dark web. 
2. Visiting malicious websites. Websites that exploit kits have compromised deploy drive-by-download attacks. This means that the user can unintentionally download malicious files while just visiting the website - without clicking any links or buttons. Other malicious websites host infected software and prey on users who interact with the content (click on links or buttons, for example) and unintentionally download infostealers in the process.
3. Downloading pirated or cracked software. Infostealers are commonly embedded in illegal software, such as cracks (tools to remove copy protection) for popular games. Bad actors exploit individuals seeking free software, while the users are unaware that their actions will result in infostealers compromising their systems.
4. Interacting with malicious advertisements. Malvertising is a technique bad actors use to entice users to engage with ads containing links with malware. Another technique, SEO poisoning, manipulates search rankings to promote malicious websites, increasing the likelihood that unsuspecting individuals will click on the infected link. 
5. Falling victim to social engineering tactics. Social engineering techniques are designed to manipulate individuals into complying with cybercriminals' objectives. Bad actors use social engineering to trick users into downloading infostealers by clicking on links in fake messages published on social media and other public networks.
6. Using infected external devices. If a USB or pen device has been compromised, infostealers can copy themselves to connected systems. However, these instances are substantially less common compared to infostealer distribution via digital channels. 

What can companies do to prevent infostealer attacks? 

From raising awareness to establishing a comprehensive cybersecurity strategy, enterprises can minimize the possibility of experiencing an infostealer attack due to user error in several ways. If you want to protect your company's systems and data, I recommend to  focus on the following: 

• Providing cybersecurity training for employees. Cyber-aware employees are the first line of defense against infostealer attacks. Users must be educated on identifying phishing and other scams and why reporting these incidents is essential.
• Employing an antivirus solution. If a user accidentally downloads infected files, an antivirus solution will aid in detecting and reporting them. This ensures that malicious software doesn't fly under the radar. 
• Downloading protection tools. These tools may automatically block malicious files before they can compromise the system. As a result, infostealers will not be able to infect the device.
• Monitoringing the dark web for previous employee data leaks. Suppose the employee's data has been compromised in the past. In that case, bad actors can use credential stuffing techniques, taking advantage of already leaked information and using automated tools to try and access business accounts until they hit the jackpot. Monitoring the dark web allows organizations to detect if employee data has been leaked and respond immediately to prevent it from being exploited.
• Enforcing effective password management practices. Using strong passwords and not re-using the same ones for different accounts helps to reduce the possibility of user credentials ending up on the dark web. 

In today's cyber threat landscape, infostealers are - and will continue to be - a substantial risk. Although anyone can become a victim of this malicious malware, organizations can significantly reduce their exposure by prioritizing cybersecurity training and implementing a comprehensive defense and response strategy.