K7TCL is proud to announce that our partnership with VirusTotal has just become stronger. Our file scanner has been on VT for ages, but we have just recently included our URL-scanning capabilities on the VirusTotal site.

We would like to take this opportunity to commend the guys at VT for their diligent work, and we very much look forward to continuing to foster our relationship with them.

Samir Mody/Lokesh Kumar
K7TCL

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We recently came across an Indian holiday booking site which appears to be serving up a copy of an old malware. Shown below is the screen shot of the site in discussion:

A quick look at the source code for the page shows an encoded binary file embedded in a VBScript:

Visiting this site with a poorly configured Internet Explorer browser will lead to the above script being rendered. The encoded file in turn is decoded and a malicious file named svchost.exe is dropped onto the user’s computer and is executed.

The malicious executable is an infamous file infector named Win32.Ramnet and detection for this executable has been around for more than a year now. This seems to suggest that the machine hosting the website has either little or no security solution in place.

With the holiday season in full swing, online shoppers are requested not to let their guard down. While you may be on holiday, the miscreants aren’t.

K7 Security products don’t just detect and delete the malicious file, but also prevent access to the hacked site:

Lokesh Kumar
K7 TCL

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It is common knowledge that phishers [Authors of a phish] attempt to steal sensitive information such as passwords, credit card details etc. by masquerading as a trustworthy entity. Some key elements of a phish are:

• A fake website created by simply ripping content off the original site and pasting them on the spurious one

• A bait which engages potentially attractive terms like “Watch nude girls now”, “You’ve won a million dollars”, “Find what your neighbor is up to “, etc. to attract victims

• Scare mongering by using words like “Account has been suspended”, “Computer found to be infected”, “Severe action will taken” etc.

• Create a YouTube video

Yes, you read that right!! Phishers now go to the depths of creating videos explaining to the potential victim how to execute the phish. Call it a “how-to-guide” to give your secrets away, if you’d like.

The site under discussion http://fbshirts.[Blocked], apart from having all the usual elements of a phish also has a video on YouTube instructing users how to give away their Facebook “mobile email address”. This is a personalized email address used to post status updates straight to your profile.

Users who’ve fallen victim to this scam will have a spam message posted on their facebook wall like the one below:

One would like to think that no one would fall victim for such a scam. But the number of hits that this video has received, (80,432 and counting) paints a bleak picture. See image below:

Our usual sentiments about keeping one’s security solutions up-to-date and being vary of giving one’s personal information to unknown sites apply.

Lokesh Kumar
K7 TCL

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We at K7 TCL came across an interesting source for a malware file to be hosted on. The site hosting the malware was the official fan site of the famous Indian playback singer Sonu Nigam.

This file has been up in the server for almost a month now. Users must exercise caution when they happen to download an executable file from a fan site that has remotely no purpose of distributing executable files to its visitors.

The malware file upon execution has capabilities to read saved passwords from a user’s internet browser, Mozilla Firefox, to be specific. It tries to read data from ‘signons[number].txt’ file found in the Firefox directory.

This text file holds the user’s logon information for websites for which the user has set ‘Remember Password’ in Firefox. Now imagine the scale of damage this could cause if the infected machine was a public computer at an internet café.
Following simple practices whenever you use a public computer would save you from such threats:

• Never save your logon information on public computers
• Always clear the history and cache before leaving the computer, or you could use the private browsing session option available in most modern browsers
• If possible use portable applications, these are applications that run out of a pen drive
• Avoid entering any kind of sensitive information on a public computer

For our customers though, it’s just a one step process: keep your antivirus definitions up to date. K7TotalSecurity detects this file, as Trojan ( 001987931 )

The server hosting the fan site has been clearly compromised. The administrators of the compromised domain have been intimated about the impending damage they might be causing to unsuspecting fans.

Kaarthik .R.M
K7 TCL

Fileave.com is a one click hosting site which provides free file hosting for its users. When compared to other similar one click hosts, the 50MB of free disk space provided by fileave.com may sound minuscule, but the fact that there’s no “wait” restrictions or CAPTCHAs to solve before downloading a file seems to make it a favourite among malware authors to host their malicious code.

The graph above displays the number of unique URLs hosting malicious files from fileave.com which were collected by our automated systems.

Closer inspection revealed that the sudden spike from ~100 URLs in the month of July to ~550 in the month of August was due to a mass compromise using the “Black-hole” exploit kit with the final payload hosted on fileave.com. The malware author responsible for this mass compromise had registered a total of ~400 unique URLs in just 1 month in the following format:

• “http://clickme[2 Random characters].fileave.com”

Discounting these URLs, the graph still shows a worrying trend:

The number of malware authors using fileave.com to host their malicious payload is on the rise. Our blog readers might recall that we had recently blogged about how malware authors abuse file hosting services with minimal security checks. The fact that fileave.com has none of these measures in place is bound to be exploited even more by malware authors in the days to come.

Lokesh Kumar
K7 TCL

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Last week at K7TCL we received a malware sample that had an interesting infection mechanism, harking back to the days of DOS companion viruses. Apart from the regular modern behaviour of dropping a self-copy and a registry entry that would initiate it on every reboot, the malware targets every program in the system that was not part of the Windows installation. It creates a copy of the respective program’s main executable and prefixes its filename with a ‘v’. So ‘abc.exe’ would become ‘vabc.exe’. Once this is done the malware then overwrites the original program executable.

The interesting malware functionality here is that it retrieves the icon from the original executable and embeds it within itself so as to masquerade as the original file.

Of course, if the original file has a shortcut and you happen to open the shortcut then this would initiate the malware file instead, since the target filename that has now been replaced by a malware.

Importantly, when the malware gets executed, it in turn initiates the original file in the folder, thereby camouflaging itself on the victim’s computer. It even sets the original program’s attribute as hidden so that the victim would be none the wiser.

In the above screenshot of process explorer it can be seen that malware file gets initiated first and it in turn calls the associated safe file.

The malware’s functionality is merely that of a companion virus, but in a modern context, GUI and all. In the DOS days, companion viruses used to exploit the fact that a file with a COM extension (the virus) always runs before a file with the same stub name but with an EXE extension (the original host). Thus running a filename from the command line without specifying the extension explicitly would result in the virus file running instead of the companion EXE host.

As in the DOS days, the modern companion virus described above can also spread from computer to computer. Consider the scenario where an unsuspecting victim shares his applications with another user. This malware would appear legitimate with its borrowed icon and filename. The sample that arrived at K7TCL had a legitimate program  icon and was not detected by any other AV at the time. Under these circumstances it would be the actual malware file and not the original program being shared, and the virus has the opportunity to do its business on a fresh computer.

K7Total Security detects this malware as Virus ( 002c651a1 )

Disclaimer: No safe files were harmed in the making of this blog post.

Kaarthik R.M
K7TCL

Here at K7TCL, we noticed a spike in the number of samples arriving with the file name “porno-rolik[2 digit number].avi.exe”. Closer inspection of the files revealed that it was yet another variant of a Ransomware. On execution, this ransomware displays a fake error message like the one shown below:

The ransomware then reboots the computer and a sexually explicit image is displayed to the user demanding him/her to dial a premium rate number and enter a code which would then unlock the machine. This particular ransomware even goes to the extent of displaying a countdown message and threatening to delete the files on the computer if the unlock code is not provided within a period of 24 hours.

Given below is a list of the URLs which were found distributing this ransomware last week:

• http://pornovirtualxxx.ru/[Blocked]porno-rolik[Blocked].avi.exe
• http://veryhotxxxporno.ru/[Blocked]porno-rolik[Blocked].avi.exe
• http://bestvideopornoxxx.ru/[Blocked]porno-rolik[Blocked].avi.exe
• http://lolkorussiangirlsporno.ru/[Blocked]porno-rolik[Blocked].avi.exe
• http://megabytespornovideo.ru/[Blocked]porno-rolik[Blocked].avi.exe
• http://pornovirtualxxx.ru/[Blocked]porno-rolik[Blocked].avi.exe
• http://smotripornomnogoxxx.ru/[Blocked]porno-rolik[Blocked].avi.exe

Our blog readers might recall an earlier blog post where we had discussed about how malware authors have gotten better at manipulating peoples behaviour to execute their code & this ransomware campaign is another example of such a scenario. Looking at the file name, the URLs which distribute them and the error message that is displayed on the malware execution suggests that this ransomware arrives as a part of a fake codec scam, possibly when a user attempts to download a video promising to deliver explicit content.

Our usual sentiments about keeping one’s security solution up-to-date & avoiding downloads from unknown sites apply.

Lokesh Kumar
K7TCL

Over the past week we came across several client submissions of ‘Personal Security Pro’, one of those highly ambitious FakeAV families that are currently prevalent.

This FakeAV, upon installation and execution, terminates almost every executable running in your system, which includes even security products. The FakeAV copies itself to a randomly named folder as “%AppData%\<randomnamefolder>\<randomnamefile>.exe” and drops a RunOnce registry trace that has a value that is equally random as the filename and folder name.

This FakeAV has an unusual behavior insofar as it drops a RunOnce entry rather than the standard Run flavour. A registry RunOnce entry is a method provided by Windows to initiate any executable for one time only upon system reboot, the RunOnce entry being deleted thereafter. Hence the life of this registry entry is just one reboot. Thus when you boot back the system and search for any malicious traces in the registry you wouldn’t find any, however the FakeAV would have got initiated. This FakeAV, on getting executed, terminates most processes that are not core system processes. One of the executables it allows us to run is ‘Explorer.exe’. After terminating the processes it drops the RunOnce registry entry again. The cycle is repeated on the next reboot.

The functionality to terminate running processes and prevent new ones from starting up is done in an attempt to circumvent the clutches of security software. In fact, the RunOnce key is added in a strategically temporal manner to avoid it being flagged by HIPS (Host Intrusion Prevention System) rules, ubiquitous in Anti-Virus products these days. HIPS is a method of blocking dynamic malware activity. In the case of the K7 TS11 product, with its robust self-protection, the FakeAV’s attempts at termination are futile, and the malware file gets flagged and quarantined without a problem.

Kaarthik R.M
K7TCL

The malware economy is always evolving and always looking out for better ways to make maximum utilization of minimal resources. Storing malicious files for retrieval at a later period, for example, was done on already infected web servers. But that meant that the malware authors were at the mercy of the system administrator monitoring that server. The moment the infected files were identified, the server hosting the malicious files would go down and the malware life cycle would thus come to an end.

The successful businessmen that they are during these harsh economic times, the malware authors then decided to include file hosting services in their arsenal. A file hosting service, as you might know, provides online storage of files. Radpishare, Megaupload, Filesonic etc. are all examples of such a service. This shift enabled the malware authors to pass on the bandwidth and disk storage cost to these sites. In addition, the reputation associated with these sites not only meant that the chances of the malicious files now being identified & reported became low, but also that the naive users were more likely to execute these malicious files, thereby increasing the malware’s time to live.

The file hosting services then brought in some checks, whereby, premium users of these sites could download files instantly at unrestricted download speeds, but regular users experienced delayed starts of downloads and restricted downloads speeds. Although unintentional, this served as a security feature in that the users were forced to look at the website before he/she could download the file. Given below is a screenshot of the countdown timer that is displayed to a regular user while downloading a file for free:

However, the opportunistic malware authors have managed to circumvent this check. This allows them to fetch the malicious files onto their victim’s machine without any user interaction whatsoever. Given below is an example of such malicious URLs which when clicked will download the file without displaying the initial countdown screen:

• http://dl.dropbox.com/u/12138956/java[Removed].exe
• https://rs533l33.rapidshare.com/files/3874050200/facebook_[Removed]jpeg.exe
• http://uppit.com/p19geeksdu4c/Premium[Removed].exe
• http://filesonic.com/file/65464647/Profesor[Removed].exe

While most of these hosting services have a system in place where unlawful contents can be reported, design flaws such as these might go unnoticed. At K7TCL, we strongly urge these file hosting services to identify and fix such design flaws in their site as soon as possible. We also suggest that they run an anti-virus solution to detect such malicious files, since their apparent laxness in this regard is helping the bad guys deliver their malware.

A digital signature applied to an object is meant to verify that the object comes from a known source, and also that the file has not been tampered with subsequently. In addition, the source of the software would have been registered with a well-known certificate authority which confers on the source an aura of legitimacy, and thus a vicarious trust on the signed object.

The mere presence of a digital signature, however, does not intend that the file in question is clean. Malware authors can and do exploit the misconception of trust associated with digital signatures to defraud the user into running their wares. The Zeus family of malware, for example, used self-signed certificates masquerading as a certificate from a legitimate company. The Stuxnet malware generated digital signatures using stolen private keys.

When legitimately signed software exhibit questionable behaviour, it leads to complications. Such applications come from software distributors who digitally sign their code and make it appear clean by bundling them with other legitimate applications. A colleague from the Anti-Virus community had recently blogged about one such software distributor – Pinball Corp., whose software displays dubious behaviour. The software comes bundled with installers for legitimate media related software like:

• XVid Codec
• FLV Codec
• VLC Player etc.

At K7TCL, we’ve been noticing that these digitally signed installers come with a new checksum almost everyday over the last couple of months, and that this trend is still continuing. One wonders why a company claiming to distribute legitimate applications would employ:

• Server-side polymorphism – A technique used by malware authors to avoid being detected by security vendors
• Missing codec scam – A social engineering technique used by malware authors to lure victims into running files

The ethical use of digital signatures states that a digital certificate can be revoked if mis-representation of software behaviour is suspected. But what constitutes this mis-representation? It seems that either the certificate issuing authority is unaware of this abuse, or perhaps it is aware, but is unwilling to act upon it. Either way, the security vendors may be left with no choice but to take matters into their own hands. These files, despite having a legitimate digital signature, are detected as Adware/Spyware by most Anti-Virus vendors.

Lokesh Kumar
K7 TCL