Cybercriminals are delivering Smoke Loader malware via a new malvertising campaign that uses health tips and advice to lure end users to a malicious website hosting the Terror Exploit Kit.

Malvertising is the name given to malicious adverts that appear genuine, but redirect users to phishing sites and websites that have been loaded with toolkits – exploit kits – that probe for unpatched vulnerabilities in browsers, plugins, and operating systems.

Spam email is the primary vector used to spread malware, although the threat from exploit kits should not be ignored. Exploit kits were used extensively in 2016 to deliver malware and ransomware, and while EK activity has fallen considerably toward the end of 2016 and has remained fairly low in 2017, attacks are still occurring. The Magnitude Exploit it is still extensively used to spread malware in the Asia Pacific region, and recently there has been an increase in attacks elsewhere using the Rig and Terror exploit kits.

The Smoke Loader malware malvertising campaign has now been running for almost two months. ZScaler first identified the malvertising campaign on September 1, 2017, and it has remained active throughout October.

Fake advertisements are frequently used to lure users to the malicious sites, although the latest campaign is using weight loss promises and help to quit smoking to attract clicks. Obfuscated JavaScript is incorporated into adverts to redirect users to malicious websites hosting the Terror exploit kit.

Exploit kits can be loaded with several exploits for known vulnerabilities, although the Terror EK is currently attempting to exploit two key vulnerabilities: A scripting engine memory corruption vulnerability (CVE-2016-0189) that affects Internet Explorer 9 and 11, and a Windows OLE automation array RCE vulnerability (CVE-2014-6332) affecting unpatched versions of Windows 7 and 8. ZScaler also reports that three Flash exploits are also attempted.

Patches have been released to address these vulnerabilities, but if those patches have not been applied systems will be vulnerable to attack. Since these attacks occur without any user interaction – other than visiting a site hosting the Terror EK – infection is all but guaranteed if users respond to the malicious adverts.

Smoke Loader malware is a backdoor that if installed, will give cybercriminals full access to an infected machine, allowing them to steal data, launch further cyberattacks on the network, and install other malware and ransomware. Smoke Loader malware is not new – it has been around since at least 2011 – but it has recently been upgraded with several anti-analysis mechanisms to prevent detection. Smoke Loader malware has also been associated with the installation of the TrickBot banking Trojan and Globelmposter ransomware.

To protect against attacks, organizations should ensure their systems and browsers are updated to the latest versions and patches are applied promptly. Since there is usually a lag between the release of a new patch and installation, organizations should consider the use of a web filter to block malicious adverts and restrict web access to prevent employees from visiting malicious websites.

For advice on blocking malvertisements, restricting Internet access for employees, and implementing a web filter, contact the TitanHQ team today.