• Cybersecurity fingerprinting refers to a set of information that can be used to identify network protocols, operating systems, hardware devices, software among other things.
• Hackers use fingerprinting as the first step of their attack to gather maximum information about targets.

The backdrop

Fingerprinting, also known as footprinting, can be deployed as a security measure to authenticate users.

• However, attackers exploit this to identify vulnerabilities in the target systems that they can exploit.
• Fingerprinting can provide attackers with valuable information such as OS type, OS version, SNMP information, domain names, network blocks, VPN points, and more.
• To gather details about the target’s network, the attackers usually launch custom packets.
• When these packets receive a response from the target network in the form of a digital signature, the OS, software, and protocols can be deduced by the attackers.
• This allows them to customize the attack to cause maximum damage to the target systems.

Types of fingerprinting

Fingerprinting techniques rely on detecting patterns and observing differences in the network packets generated. There are two types of fingerprinting — active and passive.

• Active fingerprinting involves sending TCP or ICMP packets to a system and analyzing the response from the target. The packet headers contain various flags that cause different operating systems and versions to respond differently.
• However, active fingerprinting brings with it the risk of easy detection.
• Passive fingerprinting techniques are stealthy in nature as they do not involve sending any packets to the target system. They rely on scanning the network as sniffers to detect patterns in the usual network traffic.
• Different operating systems have different TCP/IP implementations. Passive fingerprinting uses this to determine the possible OS used by the target.
• After a fair amount of data is gathered, it can be used to analyze the target system. This technique is considered less accurate than active fingerprinting.

Defensive measures

Organizations must regularly implement active and passive fingerprinting techniques on their networks to understand an attacker will be able to access. This information can assist in enhancing the OS and network security. Apart from this, there are a few other measures organizations can implement.

• Ensure that web servers, firewalls, intrusion prevention systems, and intrusion detection systems are properly configured and monitored to restrict active fingerprinting by attackers.
• Network interface cards must not be enabled to work in promiscuous mode unless absolutely necessary. In such cases, they must be strictly monitored to prevent passive fingerprinting attacks.
• Regularly monitor the log files for any sign of unusual activity.
• System administrators must patch security vulnerabilities as soon as possible.