Monday, June 13, 2011

Lenny Zeltser on Information Security — 6 Ideas for a Protean Information Security Architecture

6 Ideas for a Protean Information Security Architecture

Proteus, as envisioned by Andrea Alciato. Source: Wikipedia

Proteus, a sea god, could change his shape to confuse adversaries and avoid capture. Thinking along these lines, I wonder how the security architecture of networks and applications might incorporate protean properties, making it harder (more expensive and time-consuming) for attackers to compromise our defenses?

An environment that often changes may be harder to attack, but it is also hard to manage. In fact, many vulnerabilities seem to be associated with our inability to securely and timely implement changes, such as deploying security updates or disabling unnecessary services.

To create a protean security architecture, we’ll need to think asymmetrically: what attributes can complicate attackers’ jobs more than they complicate the jobs of defenders? I am not sure how to do this, but I have a few ideas to get started:

  • Open “fake” ports on your perimeter firewall using a script, so that an external attacker is misinformed about what services are accessible from the Internet. Redirect the connections to low-interaction honeypots.
  • Rather than blocking or dropping traffic on the perimeter firewall, configure the device to send TCP packets that indicate a transmission error, making it hard for the attacker to distinguish between a bad connection and a blocked port.
  • Deploy honeytokens on your web server to mimic the appearance of web applications that aren’t actually installed there. This may stall and misdirect the attacker. Vary the type and location of the tokens periodically.
  • Mimic the appearance of Internet-accessible servers that seem to be accessible via protocols such as SSH by using honeypots (e.g., Kippo). This can slow down and misdirect the attacker.
  • Set up a DNS blackhole to redirect internal infected systems to websites that aren’t actually malicious by using a tool such as DNS Sinkhole. You can use a honeypot such as Dionaea to further learn about malware.
  • Use open cloud services to bring up irrelevant web and other servers that seem to be associated with your organization, but don’t host sensitive data. Periodically decommission them and bring up new ones.

My ideas seem to be gravitating towards using honeypots to implement an element of deception, but there should be other ways of creating an infrastructure that is changing slightly to confuse or misdirect attackers and their tools. Do you have any ideas?

Proteus eventually captured by Menelaus, who found a way of ambushing Proteus and chaining him down. (Menelaus had an insider’s help, having received a tip from Idothea—Proteus’ daughter.) So a protean approach to defense isn’t foolproof—it is one of the elements we may be able to incorporate into an information security architecture to strengthen our resistance to attacks.


Lenny Zeltser

My dear little ugly baby is growing. With the current type of threat organization's are facing, it really makes sense to some more thought on honeytokens.

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