ESET research team assists FBI in Windigo case 0 596

First detected in 2011, the malware campaign that later became known as Windigo was able to infiltrate around 25,000 servers over a two-year period (2012-2014), with the malicious gang behind it demonstrating a high level of technical expertise. Operation Windigo is a set of Linux server-side malware tools used to redirect web traffic, send spam and host other malicious content.

At the core of Operation Windigo is Linux/Ebury, an OpenSSH backdoor and credential stealer, using that backdoor, the attackers installed additional malware to perform web traffic redirection (using Linux/Cdorked), send spam (using Perl/Calfbot or SSH tunnels) and, most importantly, steal credentials when the OpenSSH client was used to spread further.

In 2014 ESET published a research report entitled Operation Windigo. This report was awarded the inaugural Péter Szőr Award for best technical research at VB2014 and has also been used by law enforcement to explain exactly what Windigo is to prosecutors, lawyers and judges.

ESET’s collaboration with the FBI

At ESET our job is to protect all internet users and this task often requires collaboration with others such as law enforcement. In the case of Windigo, we have collaborated with the FBI through the sharing of technical details about the malicious operation and the malware components involved. This cooperation resulted in allowing the FBI investigators to better understand the various parts of this very complex scheme.

Maxim Senakh sentenced

The following timeline outlines the occurence of events leading up to the sentencing of Maxim Senakh

  • 2015-01-13: Indictment against Maxim Senakh is produced, charging him with 11 counts.
  • 2015-08-08: Maxim Senakh is arrested by Finnish authorities at its border while returning to Russia after personal travel.
  • 2016-01-05: Finland agrees to the extradition of Senakh.
  • 2016-02-04: Senakh is extradited from Finland to the US, where he pleads not guilty to all charges against him.
  • 2017-03-28: Maxim Senakh enters into a plea agreement with the US Attorney’s Office and pleads guilty to the first count of the indictment, the remaining 10 being dismissed.
  • 2017-08-03: Senakh is sentenced to 46 months in federal prison, without the possibility of parole.

Where are we now?

Not long after Senakh’s arrest in 2015, there was a sharp decrease in the traffic redirected by Cdorked, the component responsible for sending web visitors to exploit kits or unwanted advertisement pages and this activity has not resumed. The FBI had determined that this malicious activity benefited Senakh directly.

Unfortunately, however the sentencing of Senakh has not resulted in the complete shutdown of Windigo as new variants of Win32/Glupteba, a Windows malware that has strong ties with Windigo have been identified.

In addition, the malware component at the core of Windigo, has evolved. Development has continued with changes made to the latest versions, such as evasion of most of the public indicators of compromise, improved precautions against botnet takeover and a new mechanism to hide the malicious files on the filesystem.

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Approximately US $150,000 worth of Ethereum-based cryptocurrency stolen 0 368

Online cryptocurrency website MyEtherWallet.com has confirmed that some visitors could have been temporarily redirected to a phishing site designed to steal users’ credentials and – ultimately – empty their cryptocurrency wallets.

According to reports, whoever was behind the attack may have successfully stolen approximately US $152,000 worth of Ethereum-based cryptocurrency.

However,  MyEtherWallet may not have been at fault, as the website explained in its statement:

“This is not due to a lack of security on the [MyEtherWallet] platform. It is due to hackers finding vulnerabilities in public facing DNS servers.”

British security researcher Kevin Beaumont confirms in a blog post that some of MyEtherWallet’s traffic had been redirected to a server based in Russia after traffic intended for Amazon’s DNS resolvers was pointed to a server hosted in Chicago by Equinix.

For the scheme to succeed, someone pulled off a hijack of a crucial component of the internet known as Border Gateway Protocol (BGP), to reroute traffic intended for Amazon’s Route 53 DNS service to the server in Chicago. As a consequence, for some users, entering myetherwallet.com into their browser did not take them to the genuine site but instead to a server at an IP address chosen by the hackers.

The only obvious clue that a typical user might have spotted was that when they visited the fake MyEtherWallet site they would have seen an error message telling them that the site was using an untrustworthy SSL certificate.

It seems that the attackers made a mistake in not obtaining a valid SSL certificate.

Despite the error with their SSL certificate, the hackers haven’t done badly for themselves – both in this attack and in the past. Fascinatingly, the bogus MyEtherWallet website set up by the criminals was moving stolen cryptocurrency into a wallet which already contained some US $27 million worth of assets. Inevitably that raises questions of its own – have the hackers already made a substantial fortune through other attacks, or might their activities be supported by a nation state?

In a statement Equinix confirmed that a customer’s equipment at its Chicago data center was used in the hackers’ hijacking of Amazon’s Route 53 DNS service:

“The server used in this incident was not an Equinix server but rather customer equipment deployed at one of our Chicago IBX data centers… We generally do not have visibility or control over what our customers – or customers of our customers – do with their equipment.”

Amazon however, do not find the blame to lie on themselves, communicating the following statement:

“Neither AWS nor Amazon Route 53 were hacked or compromised. An upstream Internet Service Provider (ISP) was compromised by a malicious actor who then used that provider to announce a subset of Route 53 IP addresses to other networks with whom this ISP was peered. These peered networks, unaware of this issue, accepted these announcements and incorrectly directed a small percentage of traffic for a single customer’s domain to the malicious copy of that domain.”

Some advice from award winning security blogger, researcher and speaker, Graham Cluley – avoid putting your cryptocurrency wallet online, keep them off your smartphone or computer and perhaps instead invest in a hardware wallet.

Beware: ad slingers thinly disguised as security apps 0 391

Fake Security App

According to AV-Comparatives, an independent testing organization, there are significant differences in the level of protection provided by mobile security solutions. However, even the least secure of them are still far better than questionable apps that impersonate security applications in order to display ads to users. Thirty-five such applications have recently been discovered in the Google Play official Android app store.

These apps have Google Play statistics showing a minimum of over six million installs, cumulatively. However, not all those were necessarily real installations, it is possilbe that many were bot downloads posting fake reviews to improve the ratings for the app.

All 35 apps have been flagged by ESET and eventually removed from the store.

In addition to annoying their victims with ads, disguising these apps as security software has some serious negative side effects, too. In mimicking basic security functions – in fact, they all act as very primitive security checkers relying on a few trivial hardcoded rules – they often detect legitimate apps as malicious. And last but not least, they create a false sense of security in the victims, which might expose them to real risks from malicious apps that are not detected as such.

ESET’s analysis has shown that among these 35 apps, only a handful stand out for their specific features: one app is not completely free as it offers a paid upgrade; one app has implemented a primitive, easily bypassed, app-locker manager; another app flags other apps from this group as dangerous by default; and finally, one misuses ESET’s branding.

 

Security-mimicking functionality
In order to stay under the radar, all the shady ad-displaying apps mimic actual mobile security solutions. However, their ‘detection mechanisms’ are incomplete and very primitive, which makes them easy to bypass and prone to false positives.

Our research into these questionable apps has shown that their ‘detection mechanisms’ can be divided into four categories. These mechanisms are identical or almost identical across the whole set of apps.

1) Package name whitelist & blacklist
These whitelists features popular apps such as Facebook, Instagram, LinkedIn, Skype and others. The ‘blacklists’ contains far too few items to be considered security functionality at all.

2) Permissions blacklist
All apps (including legitimate ones) are flagged if they require some of the listed permissions that are considered dangerous, such as send and receive SMS, access location data, access the camera, etc.

3) Source whitelist
All apps but those from the official Android store, Google Play, are flagged – even if they are completely benign.

4) Activities blacklist
All apps that contain any of the blacklisted activities: that is, parts of applications. This mainly concerns some ad-displaying activities.

Flagged are all apps that contain any of the blacklisted activities, i.e., packages of application that are used in an application. These packages can handle additional functionalities (mainly some ad-displaying activities).

While there is nothing wrong with the idea of activity blacklisting, the implementation in these questionable apps is rather sloppy. For example, Google Ads is included in the blacklist despite the fact that it is a legitimate service. On top of being legitimate, this service is implemented in all of the shady apps we analyzed.

Additional security “functionality”
Some of the questionable security apps are capable of protecting a user’s apps with a password or a pattern locker. The idea behind this seemingly useful feature is to provide the user with another layer of security in selected apps.

However, due to insecure implementation, this feature also fails to provide true security to the user.

The problem is that relevant information is not stored safely on the device – instead of using encryption, which is common baseline practice in cybersecurity, these apps store the names of locked apps and the passwords to unlock them as plaintext.

This means that the data can be accessed after the device is rooted.

Besides compromising the unencrypted data by rooting the phone, there is another way to bypass the app lock. An attacker with physical access to the device can change the app-locking password without knowing the old one!

Conclusion
Having a security solution installed in an Android phone is definitely a good thing. However, not all apps featuring “security” or “antivirus” in their name do what the name promises. Before installing a security solution, think twice: is it really a tool you can safely rely on?

The 35 pseudo-security apps described in this article are not, say, ransomware or other hardcore malware. The only harm they do is displaying annoying ads, making false-positive detections and giving the victim a false sense of security. However, those millions of unwary users who downloaded them could easily have ended up downloading true malware in some similar disguise.

Instead of shady apps with flashy names and icons and outlandish, unsubstantiated promises, seek a reputable security solution. And which one to choose? An independent test by a well-respected testing organization might help.