Undoubtedly, Netcat can be used universally in networks and performs many helpful tasks here. So, it’s no wonder that it is extremely popular among system and network administrators – particularly since creating Netcat code becomes relatively easy after a certain amount of time.
But there is also a downside: Netcat is a hacking tool used for spying on networks, seeking out vulnerabilities, circumventing fire walls, and exploiting backdoors for taking over computers. Anti-virus programs sound the alarm, for example, when a Netcat version is found on the computer which enables execution of the option “-e” due to a special compilation.
Using this “-e” in the code, an interactive interface (backdoor shell) can be started on a remote computer. Anyone who gains unrestricted access to the cmd.exe on Windows can inflict a significant amount of damage. Additional malware can also be loaded via a backdoor shell. Hackers often use the Netcat parameter “-d” in the code, which allows the command prompt tool to cause trouble on Windows computers – while running invisibly in the background.
To avoid hacked versions, Netcat should only be downloaded from safe sources on the internet. Security experts also advise careful consideration on whether a tool like Netcat is even needed in the installation scope of systems (particularly frontend systems).
Another security risk: Netcat generally transmits data in clear text without encryption. For this reason, the tool should only be used in networks that are very well protected or – even better – cut off from the internet. For data transfers on the internet, the Netcat successor Cryptcat is better suited since it encrypts the data. Moreover, connections can be tunneled via SSH when transmitting security-relevant data.
The advantages and potential risks clearly show that Netcat is a tool which well-versed users, system administrators, and IT managers should carefully consider. Those who understand the advantages can benefit from the versatility and efficiency of the remote administration tool. And those who can suitably assess the dangers for the security of their own network, can take preventive measures to stop hacking attacks – or at least contain the damage.
However, the tool is now rather outdated – having emerged in hacking circles over 20 years ago. Better tools exist for a range of network activities. Besides Cryptcat, Socat is worth mentioning. It can use the network protocol SCTP in addition to TCP and UDP, works via proxy servers, and supports encryption. It also runs on all common platforms like Netcat.
But Netcat continues to enjoy special status as a streamlined and rapidly deployable all-rounder with simple command syntax. In combination with the administration tool Netsh, for example, many more options can be used for efficient network diagnostics and management.