Not long ago we wrote about a new piece of malware called ‘Trick Bot‘ which we caught in a malvertising attack via a high trafficked adult website. In the meantime, we uncovered another malvertising campaign that started at least in mid August, and which leverages decoy adult portals to spread malware. Internally, we call it the HookAds campaign based on a string found within the delivery URL.
What’s interesting in this specific attack chain is the use of adult sites injected with new rogue ad domains that change quite frequently. However, upstream traffic to those adult sites also shows a pattern of malvertising via the usual suspects. In this post, we take a look at the distribution channel and the rogue infrastructure behind HookAds.
Link with previous campaign
There is one distribution path that connects this campaign with the one we previously caught. In fact, much of the traffic sent to HookAds comes from malvertising on top adult sites that generate millions of visits a month. Visitors to the first XXX site will be redirected to the decoy secondary site via a simple malvertising chain.
Malware (Ursnif): 3d26585fac57027df4a68fa282ebfcc818aabb59ae6627325c2c4201cd2d6b80
Converting adult traffic
We estimate that at least one million visitors to adult websites were exposed to this particular campaign. Adult traffic is funneled to one of several decoy adult websites where an iframe to adult banner is injected dynamically. The ad is served from a third-party server which performs cloaking in order to detect whether this is legitimate new traffic or not.
Non-targets are served a banner ad which redirects to other adult sites, via legitimate ad networks. However, that same server can also serve a malicious script instead, whose goal is to redirect the victim to the RIG exploit kit (back in August, Neutrino EK was pushed). The overall flow can be summarized in the diagram below:
Fake ad server infrastructure
The fake ad server infrastructure grew during the past few months and our honeypots caught 3 sequential IP addresses that host over a hundred rogue ad domains. All of these domains have been registered with the intention of looking like advertising platforms. While some domains were used for long periods of time, most switched every day or so to let a new one in.
Sponsoring Registrar: EvoPlus Ltd
Name Server: NS[0-9].TOPDNS.ME
Exploit kit and payload overview
This campaign yields a fair amount of traffic that is fed to the RIG-v exploit kit, the latest (VIP) version of RIG EK. One of the early changes with RIG-v was a different landing page from the classic version, with the use of Unicode characters. Another change came more recently with new, less predictable URL patterns.
Below is a decoded portion of the RIG-v landing page (many thanks David Ledbetter) showing the new URL structure (thanks @malforsec for pinging me about it).
The Flash exploit RIG-v uses is protected by SWFLOCK, an online obfuscator/cryptor for Flash files (other EKs like Magnitude use DoSWF) which has the following very helpful features:
- Code obfuscation and encryption using our proven technology
- Prevent your SWF from running offline or on other websites
- Allow your SWF to run for a given trial period only
- Protect your SWF with a password
There were a lot of payloads dropped throughout this campaign (for a partial list of hashes, please refer to the IOCs below).
The HookAds malvertising campaign is still running at the time of writing this post, with new rogue ad domains getting registered each day. We are blocking the malicious IP range to protect our customers and Malwarebytes Anti-Exploit users are also shielded against the RIG exploit kit.
188.8.131.52 184.108.40.206 220.127.116.11
adbreak.info adsads.info adsgodzilla.info adsjam.info adsloop.info adspaces.info adsplaces.info adsstock.info adsyndicate.info adszones.info adultadspace.info adultbanner.info adultmedia.info adultspace.info adzones.info bannerplant.info basicclicks.net besthookup.info betterad.info bonbonads.info bonuscpm.info bonusmedia.info boostedads.info brothermedia.info bucksdelivery.info bulbcpm.info canelonads.info chooseyourads.info clickandjoy.info clickerbonus.info clickspoint.info cometamedia.info comspacecom.info coolads.info coolbanner.info cooperloop.info cozyads.info crazycpm.info crazymedia.info deluxeads.info doodleads.info endcpm.info entropymedia.info exxtraprofit.info famousads.info fancyads.info ferroad.info ferromedia.info findsilver.info flashspots.info fortynn.info foxycpm.info freehookuper.info freshcpm.info freshmedias.info frogbigfrog.info front-page.info frontrows.info frtyd.info frtyegt.info frtyeht.info frtyff.info frtyffe.info frtyfr.info frtys.info frtysvn.info frtysx.info frtyten.info fruitsmedia.info fullpagecpm.info funnycpms.info geniusmedia.info globuscpm.info gogobanner.info goldcpm.info goldenmedias.info hookupfind.info hookupmatch.info hookupsearch.info hopstops.info jockermedia.info kilomedia.info luxuryads.info madiabonus.info mamasmedia.info mediadelux.info mediaoffer.info mediaqboost.info mediasforest.info mediashouse.info mediaspot.info mediasupply.info mediaszone.info mediaszones.info mediawonder.info mightycpm.info mindflash.info monkeybusy.info monstercpm.info multiads.info okandok.info pandasmedia.info papasads.info parishads.info penads.info pointofprofit.info popularmedias.info porkymedia.info postermedia.info profitbanner.info promolinks.info promorobot.info prormohookup.info pushtheads.info randomads.info rangoomedia.info rearmedia.info revolverads.info richcpm.info safemedia.info scrollpgp.com sensecpm.info shockdelivery.info silentmedia.info silvermedias.info smarterads.info sputnikads.info standupmedia.info startmedia.info staycold.info supperpromo.info swagads.net sweeptip.info swipeflirts.info swipesflirt.info takemeup.info thousandads.info trafficprofit.info trustedmedias.info ugetmore.info uniquemedias.info vertigoads.info whitecpm.info wideads.info wildwildmedia.info yoursbanner.info zorroads.info
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