Decoding ZeuS Malware Disguised as a .DOC

[Ronnie] recently posted about his adventures in decoding malware. One of his users reported a phishy email, which did indeed turn out to contain a nasty attachment. The process that [Ronnie] followed in order to figure out what this malware was trying to do is quite fascinating and worth the full read.

[Ronnie] started out by downloading the .doc attachment in a virtual machine. This would isolate any potential damage to a junk system that could be restored easily. When he tried to open the .doc file, he was presented with an error stating that he did not have either enough memory or disk space to proceed. With 45GB of free space and 2GB of RAM, this should not have been an issue. Something was definitely wrong.

The next step was to open the .doc file in Notepad++ for analysis. [Ronnie] quickly noticed that the file was actually a .rtf disguised as a .doc. [Ronnie] scanned through large chunks of data in an attempt to guess what the malware was trying to do. He noticed that one data chunk ended with the bytes “FF” and D9″, which are also found as the ending two bytes of .gif files.

[Ronnie] copied this data into a new document and removed all new line and return characters. He then converted the hex to ASCII, revealing some more signs that this was actually image data. He saved this file as a .gif and opened it up for viewing. It was a 79KB image of a 3D rendered house. He also found another chunk of data that was the same picture, but 3MB in size. Strange to say the least.

After finding a few other weird bits of data, [Ronnie] finally started to see more interesting sections. First he noticed some strings with mixed up capital and lowercase letters, a tactic sometimes used to avoid antivirus signatures. A bit lower he found a section of data that was about the size of typical shellcode. He decoded this data and found what he was looking for. The shellcode contained a readable URL. The URL pointed to a malicious .exe file that happened to still be available online.

Of course [Ronnie] downloaded the .exe and monitored it to see how it acted. He found that it set a run key in the registry to ensure that it would persist later on. The malware installed itself to the user’s appdata folder and also reached out repeatedly to an IP address known to be affiliated with ZeuS malware. It was a lot of obfuscation, but it was still no match for an experienced malware detective.

Lenovo Shipped PC’s with Spyware that Breaks HTTPS

If you’ve ever purchased a new computer then you are probably familiar with the barrage of bloatware that comes pre-installed. Usually there are system tools, antivirus software trials, and a whole bunch of other things that most of us never wanted in the first place. Well now we can add Superfish spyware to the list.

You may wonder what makes this case so special. A lot of PC’s come with software pre-installed that collect usage statistics for the manufacturer. Superfish is a somewhat extreme case of this. The software actually installs a self-signed root HTTPS certificate. Then, the software uses its own certificates for every single HTTPS session the user opens. If you visit your online banking portal for example, you won’t actually get the certificate from your bank. Instead, you’ll receive a certificate signed by Superfish. Your PC will trust it, because it already has the root certificate installed. This is essentially a man in the middle attack performed by software installed by Lenovo. Superfish uses this ability to do things to your encrypted connection including collecting data, and injecting ads.

As if that wasn’t bad enough, their certificate is actually using a deprecated SHA-1 certificate that uses 1024-bit RSA encryption. This level of encryption is weak and susceptible to attack. In fact, it was reported that [Rob Graham], CEO of Errata Security has already cracked the certificate and revealed the private key. With the private key known to the public, an attacker can easily spoof any HTTPS certificate and systems that are infected with Superfish will just trust it. The user will have no idea that they are visiting a fake phishing website.

Since this discovery was made, Lenovo has released a statement saying that Superfish was installed on some systems that shipped between September and December of 2014. They claim that server-side interactions have been disabled since January, which disables Superfish. They have no plans to pre-load Superfish on any new systems.

Blue light special: Earn $10 by installing spyware


Ars technica is reporting on the ruling from the FTC about the software shenanigans of Kmart and Sears. The marketing geniuses behind the parent company of Sears and Kmart decided they needed more information about the users of their website. Their solution? Offering $10 to users who install their custom software which phones home with data on just about everything they do on their computer. Not content with just browsing habits of webites, the software apparently recorded everything the user did online, including secure sessions. Under the settlement (PDF) with the FTC, Sears says they will stop collecting data and promises to destroy any and all information they’ve collected so far. Selling what websites you’ve been to, how much money you have, which prescriptions you take and what products you’re interested in for the low low price of $10 seems like a bargain.

Interview with an adware author


Philosecurity has an interview with [Matt Knox], a former coder for Direct Revenue, an adware company which was sued in 2006 by New York governor Eliot Spitzer. The interview contains some interesting details of how the adware code worked internally: it created a Browser Helper Object, then ensured that the Browser Helper Object stayed up by creating a poller to check every ten seconds and regenerate the Browser Helper Object if it had stopped running. The poller ingeniously masked itself partly by exploiting Windows’ Create Remote Thread function to run itself as a series of threads instead of as an executable.

The truly fascinating bit of the interview is how [Knox] defies your initial suspicion that he’s a complete scumbag; he started off writing spam filtering software, was hired by Direct Revenue to do traffic analysis, started writing tiny bits of code to improve the adware, and eventually wound up knee-deep in the code.  [Knox] notes that you can get ordinary people to do incredibly distasteful things if you break those things into small enough chunks and introduce them gradually.

[via Waxy]

[photo: xcaballe]