In the 1980s, cyber security was still in its infancy, and episodes like the one described by an engineer at a Brazilian subsidiary of a major bank highlighted the weaknesses of the time. He described how criminals, using techniques similar to packet sniffing, intercepted ATM transactions by recording the signals exchanged between the machine and the bank, which at the time did not use encryption. Although the solution emerged with the inclusion of new elements to the transactions, such as time data, the episode highlighted the risks associated with intercepting data in transit, a practice that continues to evolve to this day.
Today, this technique is known as packet sniffing, a method used to capture and analyze data packets transmitted over networks. IT professionals use sniffing tools to detect problems, but hackers can also exploit them maliciously to access confidential information. This article explores the dangers of packet sniffing, highlights real case examples and presents practical solutions for protecting networks and data against this threat.
What is packet sniffing and why is it dangerous?
Packet sniffing refers to the interception and analysis of data packets traveling over networks. Specialized tools used in packet sniffing allow professionals to identify problems and anomalies in networks, but can also be used to access sensitive data that is not protected by encryption.
A recent example of this is the Federal Police investigation in 2022, which in turn revealed a criminal organization in Teresina (PI) manipulating the network of INSS agencies to reactivate suspended benefits. In addition, by using sniffing devices, the group was able to access privileged information and, as a result, caused considerable financial losses.
Sniffing in wireless networks
Wireless networks represent fertile ground for sniffing attacks, especially given the ease with which devices can connect. For example, in 2016, during the Mobile World Congress in Barcelona, a cybersecurity company demonstrated the vulnerability of these networks by creating fake access points with attractive names such as “Airport_Free_Wifi_AENA”. In just four hours, more than 8 million data packets were captured, revealing user and device information.
This type of attack highlights how unprotected networks, especially public ones, can expose companies and users to risks. A hacker who succeeds in a sniffing attack can compromise accounts, passwords and even plan more sophisticated actions, such as targeted attacks or ransomware.
How to protect your data against packet sniffing?
1. Data encryption
Encryption is the first line of defense. Protocols such as HTTPS ensure that confidential data, such as passwords and payment information, is protected during traffic. In addition, the use of VPNs (Virtual Private Networks) is highly recommended. A VPN creates an encrypted “tunnel” between the user and the server, protecting not only the data in transit, but also the IP addresses involved in the communication.
2. Avoid public Wi-Fi networks
Public networks are undoubtedly high-risk environments for sniffing. Therefore, avoid connecting to unknown access points, especially those with suggestive or generic names, such as “Free WiFi”. In addition, companies should make their employees aware of these risks and, consequently, invest in secure private networks.
3. Network monitoring and maintenance
To strengthen security, companies must implement continuous monitoring tools and, in addition, carry out regular scans of their networks. In addition, keeping software up to date, segmenting internal networks and educating users about social engineering attacks are indispensable practices. In this way, risks can be significantly reduced.
Packet sniffing is a tangible threat that can compromise personal and corporate data, causing financial losses and reputational damage. However, with simple practices, such as implementing encryption, using VPNs and raising awareness about public networks, it is possible to mitigate the risks. Companies, in particular, should invest in robust security policies to protect their operations from sophisticated attacks.
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