Enterprises tend to be highly focused on keeping attackers out of their systems, but most of the actual damage happens not when the bad guys first break in, but when they're able to successfully steal data -- and the techniques they're using to do this are getting steadily more sophisticated.
One of the ways that attackers evade detection is to disguize the data before sending it out, according to a new report from Intel Security.
"They are compressing the data so that it's smaller in size, or making it look like something else," said Intel Security CTO Steve Grobman. "Or they cut it up into little pieces and send the pieces to different places, so that the attacker can then pick up all the chunks and reassemble them."
Many common, legitimate avenues can be used to do this.
For example, if a company's employees post pictures to Twitter, attackers can embed data into images so that the image still looks normal to the human eye, and attach the image to an otherwise harmless-sounding Twitter post.
"The attacker can then follow the Twitter feed," said Grobman. "It looks legitimate but it is actually smuggling data out."
Gmail can also be used to smuggle data out, especially when the traffic is encrypted, he added.
Another way attackers are using to hide their behavior is to leverage processors not normally monitored for suspicious activity -- like graphics processors.
"The GPU might be used to run a domain generation algorithm to identify domains for exfiltration," said Grobman. "Because the GPU is a separate processor, you would not be able to see some of the math or algorithms running on it."
Fortunately for security professionals, the GPUs are limited in what they can actually do, he added.
"Although you do get isolation by running on the GPU, you still need to interact with the rest of the system to do something useful," he said.
To deal with the latest advances in exfiltration technology, companies need to look at their data in a new way, said Grobman.
For example, it's not just about credit card data or intellectual property anymore. Companies need to identify all the data sources that are potentially interesting to attackers, and this has grown in scope with the latest attacks, he said.
"Hacktivists are looking for information that can embarrass, things that we haven't normally thought of as high-value intellectual property, like executives' email," he said.
Then companies need to analyze how that data is supposed to move within the company, look at mechanisms they can put in place to monitor those data flows, and restructure their access controls.
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