REvil

3 Articles

This Week In Security: Unicode Strikes, NPM Again, And First Steps To PS5 Crack

November 12, 2021 by 33 Comments

Maybe we really were better off with ASCII. Back in my day, we had space for 256 characters, didn’t even use 128 of them, and we took what we got. Unicode opened up computers to the languages of the world, but also opened an invisible backdoor. This is a similar technique to last week’s Trojan Source story. While Trojan Source used right-to-left encoding to manipulate benign-looking code, this hack from Certitude uses Unicode characters that appear to be whitespace, but are recognized as valid variable names.

const { timeout,ㅤ} = req.query;
Is actually:
const { timeout,\u3164} = req.query;

The extra comma might give you a clue that something is up, but unless you’re very familiar with a language, you might dismiss it as a syntax quirk and move on. Using the same trick again allows the hidden malicious code to be included on a list of commands to run, making a hard-to-spot backdoor.

The second trick is to use “confusable” characters like ǃ, U+01C3. It looks like a normal exclamation mark, so you wouldn’t bat an eye at if(environmentǃ=ENV_PROD){, but in this case, environmentǃ is a new variable. Anything in this development-only block of code is actually always enabled — imagine the chaos that could cause.

Neither of these are ground-breaking vulnerabilities, but they are definitely techniques to be wary of. The authors suggest that a project could mitigate these Unicode techniques by simply restricting their source code to containing only ASCII characters. It’s not a good solution, but it’s a solution. Continue reading “This Week In Security: Unicode Strikes, NPM Again, And First Steps To PS5 Crack” →

This Week In Security: Apache Nightmare, REvil Arrests? And The Ultimate RickRoll

October 8, 2021 by 14 Comments

The Apache HTTP Server version 2.4.49 has a blistering vulnerability, and it’s already being leveraged in attacks. CVE-2021-41773 is a simple path traversal flaw, where the %2e encoding is used to bypass filtering. Thankfully the bug was introduced in 2.4.49, the latest release, and a hotfix has already been released, 2.4.50.

curl --data "echo;id" 'http://127.0.0.1:80/cgi-bin/.%2e/.%2e/.%2e/.%2e/bin/sh'

If that returns anything other than a 403 error, your server may be vulnerable. It’s worth pointing out that Apache is shipped with a configuration block that mitigates this vulnerability.

# Deny access to the entirety of your server's filesystem. You must
# explicitly permit access to web content directories in other
# blocks below.
#
<Directory />
AllowOverride none
Require all denied
</Directory>

The Day The Internet Stood Still

You might have noticed a bit of a kerfluffel on the Internet on Monday. Facebook dropped out for nearly six hours. While the break was nice for some, it was a major problem for others. What exactly happened? The most apparent cause was that the Facebook.com domain was returning nxdomain to DNS lookups. This led to some fun tweets, with screen caps showing Facebook.com for sale.
Continue reading “This Week In Security: Apache Nightmare, REvil Arrests? And The Ultimate RickRoll” →

This Week In Security: REvil Goes Dark, Kaseya Cleanup, Android Updates, And Terrible Firmware

July 16, 2021 by 16 Comments

The funniest thing happened to REvil this week. Their online presence seems to have disappeared.
Their Tor sites as well as conventional sites all went down about the same time Tuesday morning, leading to speculation that they may have been hit by a law enforcement operation. This comes on the heels of a renewed push by the US for other countries, notably Russia, to crack down on ransomware groups operating within their borders. If it is a coordinated takedown, it’s likely a response to the extremely widespread 4th of July campaign launched via the Kaseya platform. Seriously, if you’re going to do something that risks ticking off Americans, don’t do it on the day we’re celebrating national pride by blowing stuff up.

Speaking of Kaseya, they have finished their analysis, and published a guide for safely powering on their VSA on-premise hardware. Now that the fixes are available, more information about the attack itself is being released. Truesec researchers have been following this story in real time, and even provided information about the attack back to Kaseya, based on their observations. Their analysis shows that 4 separate vulnerabilities were involved in the attack. First up is an authentication bypass. It takes advantage of code that looks something like this: Continue reading “This Week In Security: REvil Goes Dark, Kaseya Cleanup, Android Updates, And Terrible Firmware” →