Cybercriminals have been using the Neptune exploit kit to deliver cryptocurrency miners via malvertising campaigns, FireEye reported on Tuesday.
Neptune, whose arrival was detailed by researchers in January, is also known as Terror, Blaze and Eris. It was initially considered a variant of the Sundown exploit kit due to many code similarities.
Exploit kit activity has been declining since the disappearance of Angler and Neutrino. Sundown also went silent and the infosec community managed to delivered a significant blow to the infrastructure used by RIG.
Neptune has gained popularity and it continues to be used in malvertising campaigns, particularly ones that aim to deliver cryptocurrency miners. Several changes have been spotted recently by FireEye in Neptune attacks, including URI patterns, landing pages, malvertising campaigns and payloads.
The new URI patterns were first observed by FireEye in mid-July. The attackers have been abusing a legitimate pop-up ad service (present in Alexa’s Top 100) to deliver malware via fake advertisements for hiking clubs. The malicious websites imitate real domains, often using the same domain name with a .club suffix instead of .com (e.g. highspirittreks.com vs highspirittreks.club). One of the domains used to redirect users to the exploit kit landing pages also mimics a YouTube to MP3 online converter.
The ads linked to this Neptune exploit kit campaign have been typically served on popular torrent and hosting websites.
Once victims are taken to the landing page, the EK exploits three Internet Explorer and two Adobe Flash Player vulnerabilities to deliver malware. None of the exploits used by Neptune are new – they target vulnerabilities disclosed between 2014 and 2016.
The payload delivered in the campaign is a piece of malware that mines for Monero (XMR), a cryptocurrency currently worth roughly $86 per unit.
The regions most affected by the campaign are South Korea (29%), Europe (19%), Thailand (13%), Middle East (13%) and the United States (10%).
“Despite an observable decline in exploit kit activity, users are still at risk, especially if they have outdated or unpatched software,” FireEye warned. “This threat is especially dangerous considering drive-by exploit kits (such as Neptune EK) can use malvertisements to seamlessly download payloads without ever alerting the user.”
Related: Terror Exploit Kit Rising as Sundown Disappears