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Threat Actors Evade Detection Through Geofencing & Fingerprinting

Security teams may be missing targeted attacks and advanced exploits if attackers are using evasive techniques to avoid detection. Defenders need to up their game.

Attackers today combine state-of-the-art obfuscation and adaptive environment-specific features to avoid detection by traditional malware analysis systems. If your security team is relying on legacy approaches, like traditional sandboxing, to scan files entering your network, they may miss these dangerous exploits targeting your organization. If your security teams are spending their time with easy-to-detect, common vulnerabilities and not on the targeted attacks, they are exposing your organization to unnecessary risk from cybercriminals.

Nothing about this pattern is new: Researchers develop new anti-malware technology to detect malware attacks. Cybercriminals adapt their malware variants to avoid detection. And the cycle continues.

Attackers are adopting techniques, such as machine fingerprinting and geofencing, where they use information about the victim's application stack and system environments to compromise systems.

Gotta Catch 'Em All: Geofencing

There are many ways for malware to get on a victim's machine. Once there, some malware variants remain dormant if the victim's machine or network is not in a specific country. That comes courtesy of geofencing.

The malware looks up the external IP address geographic region via an external database or service and checks whether the device is located in the target region. If the device's geographic location is in a region of interest, the malware detonates. It may install a second-stage malware; steal useful information, such as administrator credentials; exfiltrate data to a system controlled by criminals; and remove all traces of its activity on the machine.

Attackers add geofencing features to malware for many reasons. It may be easier to evade detection by locations with strong security postures. Sometimes they don't want to infect networks in their home countries, where they could face prosecution. Savvy criminals target wealthy countries inhabited by trusting folks who are more likely to open documents and pay ransom. Or they may know that business leaders in a specific region rely on weak defensive postures or are less likely to use two-factor authentication.

One example of a region–specific attack: The South Korean government widely uses the Hangul Word Processor (HWP). North Korean attackers write malware in Hangul to penetrate critical government systems. Trying to use this malware to compromise US government employees, however, would be a waste of resources.

Finding the Golden Image: Fingerprinting

Malware authors rely on diverse fingerprinting techniques to determine whether machines are susceptible to their attack chains. Fingerprinting helps malware avoid detection by appearing harmless to antivirus technologies.

The malware remains dormant on the victim's machine unless the environment meets predefined conditions — such as having a specific application installed or certain configuration settings enabled. Attackers also use fingerprinting techniques to figure out whether the compromised system is actually a virtual machine using a preconfigured, out-of-the-box or initial install image. If that is the case, the malware does not detonate.

What Adaptive and Dynamic Analysis Looks Like

Traditional sandboxes may not detect advanced malware or targeted zero-day attacks if the attacker is using techniques such as geofencing or fingerprinting. For example, malware that uses geofencing must look up IP addresses to determine its geographic location. In contrast, adaptive dynamic analysis technology can help detect very specific, targeted attacks because it can detect and automatically bypass environment and anti-analysis checks. 

Adaptive analysis performs execution only of instructions related to the malware, as opposed to traditional sandboxes, which are fully virtualized operating systems executing instructions of every service and application on the system. As a result, the total resource utilization for adaptive analysis is significantly lower. Being able to extract intelligence in the form of indicators of compromise (IOCs) enables threat hunting, proactive self-defense improvements, and threat actor attribution.

Editors' Choice
Robert Lemos, Contributing Writer, Dark Reading
Shikha Kothari, Senior Security Adviser, Eden Data