Thursday, October 18, 2012

UPS spam downloads malware

Yes, you've read the title right. Not the usual spam/malware attachment, but in fact just a picture of UPS... which of course is clickable.

But wait! Seems like the bad guys forgot a letter in their HTML (facepalm). I received the following mail:

Subject of spam email: UPS #Print your postal label

Since they forgot the "h" in "http", the image is incorrectly displayed. What it should have been:

Your package was not delivered. You are asked to print the label 

The mail  is coming from (related to the Asprox botnet): - IPVoid Result

What happens when you click on the "Print a shipping label" (or what it should have been):

A ZIP file gets saved, but you still need to open it and execute the file to become infected...


Result: 13/43
MD5: 2e9755cfce544627fbfd3be07af5d7d9
Anubis Report
Malwr Report
ThreatExpert Report 

If the file gets executed, it drops a copy of itself to the %appdata% folder and tries to connect to the following IPs: - IPVoid Result - IPVoid Result - IPVoid Result - IPVoid Result - IPVoid Result - IPVoid Result - IPVoid Result - IPVoid Result - IPVoid Result

Also when executing the file, an instance of svchost (malware injected into it, thanks to SteveK for the headsup) gets started and opens an empty Notepad file:
Empty Notepad file created by the malware

If anyone has an idea on the why of this,be sure to let me know. Maybe to convince you it's really a UPS label after all? Second fail of the day, should have at least included some rubbish text in there.

This malware is known as Kuluoz, which can download and install additional malware on your system.


Pretty simple. Never open any emails from unknown senders, do not click on any links and certainly do not open any attachments.

Bells should be ringing already when you have not ordered anything. Always be wary when receiving mails where you need to click on a link or open an attachment to view this or that. Ask yourself:
"does this look legit?" If the answer is no, you know what to do.

Monday, October 8, 2012

Worm spreading through Skype and Messenger

Since Saturday, there's a worm actively spreading through (mainly) Skype as well as Messenger (Windows Messenger, Microsoft MSN Messenger).

Someone who's infected with this worm will send you the following message:

Message in German asking to check your cool pictures

The link refers to and is actually Google's URL Shortener service. You'll land on, which is a legitimate file sharing website. (it's not the first time Hotfile has been used to spread malware, read more here. The file has already been removed by Hotfile.)

Links refers to Hotfile and will immediately download a ZIP file.

Positive thing is that it is a ZIP file and not an EXE. This means the user still has to manually unpack and run the malware. Inside our ZIP file we'll find the following file, which is covered as a Skype setup file:

Looks like the real deal. But it's not.

When executing this file, another file (a random 4 character EXE) will be dropped to the %appdata% folder of the currently logged on user:

The icon suggests it's uTorrent. But it's not.

This file will try to connect to, waiting for instructions. Additionally, it tries to connect to the following IP addresses: - IPVoid Result - IPVoid Result - IPVoid Result - IPVoid Result - IPVoid Result - IPVoid Result

Now, how do we know how it spreads and which messages it can display? The file extracted from the ZIP archive - skype_05102012_image.exe looks for the following processes:

It will then automatically send a message, based on the OS language. It uses the following list to spread:
tas ir jusu jauna profila bildes?
seo do grianghraf prl nua?
ont uusi profiilikuva?
nai aft a fotografa profl sas?
sa kvo profili lusankary aquesta
s la teva nova foto de perfil?
hey ito sa iyong larawan sa profile?
hey lanh tieu cua ban?
hey ini foto profil?
hei zhni de gn zilio zhopin ma?
ni phaph porfil khxng khun?
hej er det din nye profil billede?
hej je to vasa nova slika profila?
hej je to tvuj nov obr zek profilu?
hei er dette din nye profil bilde?
hey la tua immagine del profilo nuovo?
hej to jest twj nowy obraz profil?
hej jeli ovo vasa nova profil skila?
hey bu yeni profil pic?
hej detta är din nya profilbild?
tung, cka paske lyp ti nket fotografi?
moin , kaum zu glauben was für schöne fotos von dir auf deinem profil
hey is dit je nieuwe profielfoto?
ez az j profil ksta tu foto de perfil nuevo?
hey essa sua foto de perfil? rsrsrsrsrsrsrs
hey c'est votre nouvelle photo de profil?
hoi schoni fotis hesch du uf dim profil ppe n
lol is this your new profile pic?

It will then add the link and subsequently adds your username after the equals '=' sign :

Let's take a closer look at the files:

Result: 23/44
MD5: 98f74b530d4ebf6850c4bc193c558a98
Anubis Report
Malwr Report
ThreatExper Report

Result: 16/44
MD5: 0d4b7f4c1731c91dff56afce0ecf37c5
Anubis Report
Malwr Report
ThreatExpert Report

The malware is commonly identified as Worm.Dorkbot and Worm.Agent or Generic Trojan.

Microsoft provides a description:
Win32/Dorkbot is a family of IRC-based worms that spreads via removable drives, instant messaging programs, and social networks. Variants of Win32/Dorkbot may capture user names and passwords by monitoring network communication, and may block websites that are related to security updates. It may also launch a limited denial of service (DoS) attack.

On my testmachines there was no additional malware downloaded, even after replicating a few times. Several variants of malware can however always be downloaded, whether it's ransomware, rogueware....


Worms spreading through Facebook, Twitter as well as IRC, MSN and Skype is nothing new. Still, it appears to be very successful as human curiosity wins in cases of doubt:
"Do I really have (embarassing) pictures of myself on this website? Better take a look!"

No, no, no!

Never click on unknown links, especially when a URL shortener service like is used. (others are for example,, tinyurl, etc.)
Don't be fooled by known icons or "legit" file descriptions, this can easily be altered.

Even if you clicked the link and you're not suspicious, you should be when a file is downloaded and no pictures are shown, but just an EXE file.

For checking what is really behind a short URL, you can use:

For checking whether a file is malicious or not: