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.

Vulnerabilities / Threats

2/29/2012
07:32 PM
50%
50%

Tracking Down Advanced Threats In Your Network

If you had an advanced attacker in your network, would your security team know it? At the RSA Conference, HBGary's Greg Hoglund shared four ways to defend against pernicious attacks

' '
Click here for more articles.

RSA CONFERENCE 2012 -- San Francisco, Calif. -- The lion's share of attacks that target companies will be opportunistic scams and cybercrime, but companies that want to protect their customer information and corporate intellectual property need to also worry about the more persistent attackers.

While the term "advanced persistent threat" (APT) has become a marketing buzzword, persistent attackers do pose a real threat for companies, Greg Hoglund, founder and chief technology officer of HBGary, told attendees here today at the RSA Conference. As attackers learn the benefits of quietly establishing a beachhead inside corporate networks, corporate IT security teams need to assume that the bad guys have already made it past their defenses and actively hunt down the intruders in their networks.

"You should not rely completely on an outside vendor to supply you a magical black list that will solve all your security problems," he said.

HBGary learned the hard way that APTs do not need to use advanced techniques to get a company's critical information. A year ago, hackers claiming to be part of the Anonymous movement gained access to the e-mail accounts of the company's subsidiary HBGary Federal and leaked confidential messages. Yet the hackers never gained access to the company's network, the firm has said.

Dealing with attackers who are specifically targeting your company is a tough problem, and an expensive one, Hoglund said.

"It's a counterintelligence problem," Hoglund said. "You have to be willing to accept the cost of treating it as a counterintelligence problem, if you want good security."

Here are four of Hoglund's recommendations to help companies better find APTs in their networks.

1. Be aware of suspicious behavior.
Advanced attackers will use social engineering and other methods -- such as compromising third-party servers -- to get valid credentials to access a corporate network. At that point, it becomes nearly impossible to detect the attackers based on detecting malicious code. Instead, the defenders need to focus on identifying suspect behaviors, Hoglund said.

"Once they have done that, they may not be using exploits any more," he said. "They will just be logging in with user credentials, and that's an entirely different problem. Looking for malware ... is not enough."

Detecting strange employee behavior on the network becomes very important once credentials are compromised. In one case, for example, a group of attackers would habitually wait for a three-day weekend before exfiltrating data from the target. Companies that are sensitive to anomalous behavior can detect such activity, Hoglund said.

"If on a three-day weekend we know they will be exfiltrating data, we can be ready for it," he says.

2. Detect movement from the beachhead.
Every company wants to stop attackers from getting in, but firms should assume that -- at some point -- the attackers will infiltrate their networks. When that happens, the initial system is almost never the one in which the intruders are interested, Hoglund said.

Instead, the groups compromise any internal system and then use that beachhead to move laterally within the network. While companies should be rightfully concerned that an attacker is in the network, the intruders do generate a lot of anomalous network traffic that can give away their activities. Looking for that traffic is key, he says.

"If you can detect lateral movement inside your network, you can detect APT," Hoglund said.

3. Don't stop when you found one compromise.
Many companies will just erase a compromised server and reinstall a clean image. Yet the organization then makes it more difficult to track down other infected systems.

Instead, IT security groups should use a compromise to go find the other systems that have been infected, Hoglund said.

Advanced actors "use an entrenchment strategy," he says. "When they place a remote-access tool in the environment, they are never placing just one."

In another case, for example, HBGary had chased one group throughout a network for three months, eliminating their access. They kept looking, however, eventually finding a remote-access tool similar to the ones they had deleted but that used a copy of Microsoft's Windows Messenger as an emergency back door, just in case someone had wiped out their access.

"They are putting multiple layers of entrenchment in there so that if you find some of their stuff, you need to find all of their stuff," he says.

4. Look for the exfiltration point.
When an attacker has found valuable information, he prepares to exfiltrate the data. That's another point at which defenders can detect the attacker's presence, Hoglund said. Looking for large compressed files on servers is a good place to start.

"We see RAR used a lot for exfiltrating data, as well as CAB files," Hoglund said. RAR is a proprietary format for archiving made popular by WinRAR, while CAB files, or cabinet files, are a format used by Microsoft to compress software components for use by an installer.

By searching for RAR and CAB files on systems in the network, companies may be able to find potential exfiltration points, he said.

"And guess what? If you find a machine with a bunch of these files, you may have an exfiltration point," Hoglund said.

Have a comment on this story? Please click "Discuss" below. If you'd like to contact Dark Reading's editors directly, send us a message.

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
COVID-19: Latest Security News & Commentary
Dark Reading Staff 9/25/2020
Hacking Yourself: Marie Moe and Pacemaker Security
Gary McGraw Ph.D., Co-founder Berryville Institute of Machine Learning,  9/21/2020
Startup Aims to Map and Track All the IT and Security Things
Kelly Jackson Higgins, Executive Editor at Dark Reading,  9/22/2020
Register for Dark Reading Newsletters
White Papers
Video
Cartoon
Current Issue
Special Report: Computing's New Normal
This special report examines how IT security organizations have adapted to the "new normal" of computing and what the long-term effects will be. Read it and get a unique set of perspectives on issues ranging from new threats & vulnerabilities as a result of remote working to how enterprise security strategy will be affected long term.
Flash Poll
How IT Security Organizations are Attacking the Cybersecurity Problem
How IT Security Organizations are Attacking the Cybersecurity Problem
The COVID-19 pandemic turned the world -- and enterprise computing -- on end. Here's a look at how cybersecurity teams are retrenching their defense strategies, rebuilding their teams, and selecting new technologies to stop the oncoming rise of online attacks.
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2020-15208
PUBLISHED: 2020-09-25
In tensorflow-lite before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, when determining the common dimension size of two tensors, TFLite uses a `DCHECK` which is no-op outside of debug compilation modes. Since the function always returns the dimension of the first tensor, malicious attackers can ...
CVE-2020-15209
PUBLISHED: 2020-09-25
In tensorflow-lite before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, a crafted TFLite model can force a node to have as input a tensor backed by a `nullptr` buffer. This can be achieved by changing a buffer index in the flatbuffer serialization to convert a read-only tensor to a read-write one....
CVE-2020-15210
PUBLISHED: 2020-09-25
In tensorflow-lite before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, if a TFLite saved model uses the same tensor as both input and output of an operator, then, depending on the operator, we can observe a segmentation fault or just memory corruption. We have patched the issue in d58c96946b and ...
CVE-2020-15211
PUBLISHED: 2020-09-25
In TensorFlow Lite before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, saved models in the flatbuffer format use a double indexing scheme: a model has a set of subgraphs, each subgraph has a set of operators and each operator has a set of input/output tensors. The flatbuffer format uses indices f...
CVE-2020-15212
PUBLISHED: 2020-09-25
In TensorFlow Lite before versions 2.2.1 and 2.3.1, models using segment sum can trigger writes outside of bounds of heap allocated buffers by inserting negative elements in the segment ids tensor. Users having access to `segment_ids_data` can alter `output_index` and then write to outside of `outpu...