European government institutions and agencies have again come under attack from the Russia-linked hacking group called Fancy Bear, which also goes by the names APT28 and Sofacy, according to a new report from Palo Alto Networks.
The attacks are using a new variant of the DealersChoice exploit in order to deliver a Trojan payload, the report finds.
This exploit, which Palo Alto Networks observed between March 12 and March 14, leverages a Flash vulnerability in its operation but does so in a way that has not been seen before now.
A spear-phishing email is first directed to the victim posing as the agenda to a legitimate security conference that is soon occurring in the UK. The Microsoft Word document – "Defence & Security 2018 Conference Agenda.docx" -- that is purportedly the agenda is where the malicious action script resides. However, the malicious Flash object (covert-shores-small.png) is in the third page of the document and is only triggered if the victim views it.
The poisoned DealersChoice loader appears as a small black dot on the page and could be easily overlooked by the target.
This new technique is inherently anti-sandbox, since it requires human interaction to be performed before any malicious activity is exhibited. The particular choice of this lure document demonstrates a sophisticated social engineering component for the campaign, since anyone who is interested in the contents of it is likely to be someone that the campaign wishes to infect.
Not only that, the group behind the attack extends the self-selection of victims by waiting for them to scroll through the document to the third page. This would show the target's interest in the contents and the likelihood that they are not just a casual user.
If viewed -- and therefore activated -- the Flash object then contacts a command-and-control server to download another Flash object that has more exploit code.
The goal of the campaign seems to be a stealth compromise of the governmental system, giving the attackers a foothold into it. The organizational targets of the attack were not specified by Palo Alto Networks.
Palo Alto researchers were able to link this attack to APT28 because of the presence of a "Nick Daemoji" as the lure document's last modifier. This is a characteristic of previous Fancy Bear work, as noted in a Talos blog. Previous campaigns by the group have also used emails about upcoming military conferences as a lure.
Once again, the vulnerability of Flash is made evident by the attack. The perpetrators are counting on the lack of patching for their campaign to succeed, even though the plugs for these problems have been readily available.
— Larry Loeb has written for many of the last century's major "dead tree" computer magazines, having been, among other things, a consulting editor for BYTE magazine and senior editor for the launch of WebWeek.