Adversaries are committed to continually refining or developing new techniques to conceal malicious activity, decrease their reliance on other techniques that may be more detectable, and become increasingly more efficient and effective in their attacks. Below are just three examples-explored in detail in the newly releasedCisco 2015 Annual Security Report-of how malicious actors met these goals in 2014. These trends were observed by Cisco Talos Security Intelligence and Research Group throughout last year, and analyzed by the team using a global set of telemetry data:

• Use of malvertising to help deliver exploit kits more efficiently-Talos noted three exploit kits we observed "in the wild" more than others in 2014: Angler, Goon, and Sweet Orange. More than likely, their popularity is due to their technical sophistication in terms of their ability to evade detection and remain effective. The Sweet Orange kit, for example, is very dynamic. Its components are always changing. Adversaries who use Sweet Orange often rely on malvertising to redirect users (often twice) to websites that host the exploit kit, including legitimate websites.

• Increase in Silverlight exploitation-As we reported in both theCisco 2014 Midyear Security Reportand theCisco 2015 Annual Security Report, the number of exploit kits able to exploit Microsoft Silverlight is growing. While still very low in number compared to more established vectors like Flash, PDF, and Java, Silverlight attacks are on the rise. This is another example of adversaries exploring new avenues for compromise in order to remain efficient and effective in launching their attacks. The Angler and Goon exploit kits both include Silverlight vulnerabilities. Fiesta is another known exploit kit that delivers malware through Silverlight, which our team reported on last year.
  

• The rise of "snowshoe spam"-Phishing remains an essential tool for adversaries to deliver malware and steal users' credentials. These actors understand that it is more efficient to exploit users at the browser and email level, rather than taking the time and effort to attempt to compromise servers. To ensure their spam campaigns are effective, Talos observed spammers turning to a new tactic last year: snowshoe spam. Unsolicited bulk email is sent using a large number of IP addresses and at a low message volume per IP address; this prevents some spam systems from detecting the spam, helping to ensure it reaches its intended audience. There is also evidence that adversaries are relying on compromised users' machines as a way to support their snowshoe spam campaigns more efficiently. Snowshoe spam contributed to the overall increase of spam volume by 250 percent in 2014.

These are only a few of the threat intelligence findings presented in theCisco 2015 Annual Security Report. We encourage you to read the whole report, but also, to stay apprised of security trends throughout the year by following our reports on the Cisco Security blog. Talos is committed to ongoing coverage of security threats and trends. In fact, in theCisco 2015 Annual Security Report, you'll find links to several posts that our researchers published throughout 2014, and were used to help shape and inform our threat intelligence coverage in the report.