The Evolution of ShellBot Malware: A Dive into Hexadecimal Notation


Published on Oct 13, 2023   —   1 min read

Threat actors are constantly innovating to stay one step ahead. One such innovation is the use of hexadecimal notation in the distribution of ShellBot malware. AhnLab Security Emergency Response Center (ASEC) recently reported a shift in the tactics employed by cybercriminals to distribute ShellBot, a DDoS malware targeting Linux SSH servers. Let's delve into the nitty-gritty of this development, shall we?

The Old Ways: Dot-Decimal Notation

Traditionally, ShellBot was distributed using IP addresses in the "dot-decimal notation" format. This was the bread and butter of threat actors for their Command and Control (C&C) servers, download URLs, and phishing schemes. However, as detection mechanisms improved, so did the tactics of these cyber rogues.

The New Trick: Hexadecimal Notation

The latest twist in the tale is the use of hexadecimal notation for IP addresses. This is not just a cosmetic change; it's a calculated move to evade detection. For instance, the IP address "" is represented in hexadecimal as "0x2763da4e". This allows the malware to be downloaded successfully on Linux systems, bypassing many traditional detection methods.

How Does It Work?

After gaining access to a poorly managed Linux SSH server, the threat actor uses specific commands to install ShellBot. The commands remain largely the same; the only difference is the use of hexadecimal IP addresses. This allows the malware to be downloaded and executed without raising any red flags.

The Risks Involved

Once installed, ShellBot can be used for DDoS attacks and various other malicious activities. This makes it imperative for administrators to employ robust security measures, including strong passwords and up-to-date patches.

Conclusion and Recommendations

The use of hexadecimal notation in ShellBot's distribution method is a clear indication of the evolving tactics of cybercriminals. To counter this, administrators should:

  1. Use strong, unique passwords.
  2. Regularly update security patches.
  3. Employ firewalls and other security measures.

By staying vigilant and adapting to new threats, we can hope to keep our digital landscapes a bit safer.

Further Reading

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