Dark Reading is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them.Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

Perimeter

5/29/2009
04:55 AM
Gadi Evron
Gadi Evron
Commentary
Connect Directly
Twitter
LinkedIn
RSS
E-Mail
50%
50%

Cybercriminals: More Obvious Than They Think?

Attackers often use and abuse security by obscurity, which can lessen the likelihood that they will be caught. From them we can learn a lot about profiling attackers on our networks, and how they work to achieve better operational security. Take their use of encryption.

Attackers often use and abuse security by obscurity, which can lessen the likelihood that they will be caught. From them we can learn a lot about profiling attackers on our networks, and how they work to achieve better operational security. Take their use of encryption.Being obscure, attackers hope to avoid detection or compromise. The best example in recent years is binary packers.

When virus authors use packers to obfuscate and encrypt their new worm or bot, they have two achievements in mind: alluding detection by antivirus products, and making it much harder for virus researchers and reverse engineers to unravel how their malware works, thus taking more time to create detection signatures in the first place.

Let me pose it this way: It's a hot summer day, and you're drinking a beer at the beach. People are having fun and relaxing. Suddenly, you see a person wearing an heavy coat. Is this suspicious?

Most likely that is not common behavior, and your answer is YES! Now, it does not necessarily mean that person is a terrorist, but it's not a bad idea to call the police.

In much the same way, if a gateway antivirus vendor collects and correlates information from clients (while filtering billions of email messages every day), "seeing" an executable email attachment that is "packed" arouses suspicion. This sample can be marked as suspicious and tested further.

For clarification, plenty of legitimate products use packers, so false positives will occur. On the desktop antivirus, this is not a great idea.

The goal of the smart attacker is to appear like a normal user, much like a spy would try and appear inconspicuous. Many attackers are not smart. Bots are far from common users in behavior.

Packers are a form of encryption. Encryption illustrates the preceding example. If you're a spy and want to send a message to your handlers using email, then would you use encryption?

Encryption is a great tool, but it also draws attention to you for using it. In your organization, how likely is an attacker to identify important resources just by watching for encrypted traffic? In some cases, it may be better to stay obscure, in the background as noise, than to use encryption. If the malware sample is new and therefore undetected by antivirus, then the same unfortunately applies to malware authors.

Encryption is, indeed, a great tool, but it is not a cure-all. It requires a risk analysis on your part -- much like any other solution.

Even if you decide encryption is an added value by default, there are other uses for the concept that it helped us illustrate. Ask yourself: What do attackers mostly look like? Do they have something in common you should be looking for?

This is often referred to as anomaly detection, only you can use it not just in deep packet inspection, but in daily operations -- much like looking for the guy wearing a heavy coat in the summer.

Knowing what your network looks like and what traffic is typical is the most basic and most critical in corporate network security.

Two random examples of possible anomalies:

    1. Should Web servers be talking to each other in the server farm? 2. Should the firewall be surfing the Web?

What are yours?

You can read the first in this series of articles here and the second here.

Follow Gadi Evron on Twitter: http://twitter.com/gadievron

Gadi Evron is an independent security strategist based in Israel. Special to Dark Reading. Gadi is CEO and founder of Cymmetria, a cyber deception startup and chairman of the Israeli CERT. Previously, he was vice president of cybersecurity strategy for Kaspersky Lab and led PwC's Cyber Security Center of Excellence, located in Israel. He is widely recognized for ... View Full Bio

 

Recommended Reading:

Comment  | 
Print  | 
More Insights
Comments
Oldest First  |  Newest First  |  Threaded View
COVID-19: Latest Security News & Commentary
Dark Reading Staff 8/14/2020
Lock-Pickers Face an Uncertain Future Online
Seth Rosenblatt, Contributing Writer,  8/10/2020
Hacking It as a CISO: Advice for Security Leadership
Kelly Sheridan, Staff Editor, Dark Reading,  8/10/2020
Register for Dark Reading Newsletters
White Papers
Video
Cartoon
Current Issue
7 New Cybersecurity Vulnerabilities That Could Put Your Enterprise at Risk
In this Dark Reading Tech Digest, we look at the ways security researchers and ethical hackers find critical vulnerabilities and offer insights into how you can fix them before attackers can exploit them.
Flash Poll
The Changing Face of Threat Intelligence
The Changing Face of Threat Intelligence
This special report takes a look at how enterprises are using threat intelligence, as well as emerging best practices for integrating threat intel into security operations and incident response. Download it today!
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2020-17475
PUBLISHED: 2020-08-14
Lack of authentication in the network relays used in MEGVII Koala 2.9.1-c3s allows attackers to grant physical access to anyone by sending packet data to UDP port 5000.
CVE-2020-0255
PUBLISHED: 2020-08-14
** REJECT ** DO NOT USE THIS CANDIDATE NUMBER. ConsultIDs: CVE-2020-10751. Reason: This candidate is a duplicate of CVE-2020-10751. Notes: All CVE users should reference CVE-2020-10751 instead of this candidate. All references and descriptions in this candidate have been removed to prevent accidenta...
CVE-2020-14353
PUBLISHED: 2020-08-14
** REJECT ** DO NOT USE THIS CANDIDATE NUMBER. ConsultIDs: CVE-2017-18270. Reason: This candidate is a duplicate of CVE-2017-18270. Notes: All CVE users should reference CVE-2017-18270 instead of this candidate. All references and descriptions in this candidate have been removed to prevent accidenta...
CVE-2020-17464
PUBLISHED: 2020-08-14
** REJECT ** DO NOT USE THIS CANDIDATE NUMBER. ConsultIDs: none. Reason: This candidate was withdrawn by its CNA. Further investigation showed that it was not a security issue. Notes: none.
CVE-2020-17473
PUBLISHED: 2020-08-14
Lack of mutual authentication in ZKTeco FaceDepot 7B 1.0.213 and ZKBiosecurity Server 1.0.0_20190723 allows an attacker to obtain a long-lasting token by impersonating the server.