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Cryptowall 3.0: Back to the Basics

This post was authored by Andrea Allievi  & Earl Carter

Ransomware continues to impact a large number of organizations and the malware continues to evolve. In January, we examined Cryptowall 2.0 and highlighted new features incorporated into the dropper and Cryptowall binary. When Cryptowall 3.0 appeared, we were interested in seeing what new functionality was incorporated into this latest variant in the Cryptowall series.

The latest 3.0 sample that we analyzed was in a zip file. This zip file contains multiple dropper files which are essentially identical in functionality except for the encryption algorithm used to obfuscate the dropper and eventually build the Cryptowall 3.0 binary.

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Fake Volume License Trojan Targets Corporate Users and Evades Sandboxes

Two weeks ago, multiple Cisco Managed Threat Defense (MTD) customers received an email that appeared to come from the Microsoft Volume Licensing Service Center (VLSC).  The email shown below is very similar to the real email Microsoft sends.  It had a personalized welcome line and appears to contain a link to login to the Volume Licensing Service Center:

The phish email supposedly from Microsoft Volume Licensing

The phish email supposedly from Microsoft Volume Licensing

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How AMP Threat Grid Accelerates Incident Response with Artifacts, Content, and Correlation

As a result of Cisco’s acquisition last May, ThreatGRID is now part of the Cisco Advanced Malware Protection (AMP) portfolio as AMP Threat Grid. The acquisition expands Cisco AMP capabilities in the areas of dynamic analysis and threat intelligence technology, both on-premise and in the cloud. AMP Threat Grid extends Cisco AMP with even greater visibility, context, and control over sophisticated threats. Security analysts and incident response teams can augment their forensics analysis to detect and stop evasive attacks faster than ever.

AMP Threat Grid is not simply another dynamic analysis platform or sandbox. While the solution does leverage various dynamic analysis techniques and ‘sandboxing’ to produce content, it also acts as a content engine so that you can more quickly and easily extract insights from the data. AMP Threat Grid treats all of its analysis as content, making it available to the user via a portal or API. AMP Threat Grid also doesn’t stop at a single analysis technique; instead it applies multiple dynamic and static analysis engines to submitted samples – all produced disk, network, and memory artifacts – in order to generate as rich a source of data as possible.

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Be More Effective, Be More Efficient: The Mantra for Many Adversaries in 2014

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 released Cisco 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 the Cisco 2014 Midyear Security Report and the Cisco 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.

snowshoe

  • 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 the Cisco 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 the Cisco 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.

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Deliver Stronger Secure Mobility with Cisco and Samsung

The growing use of mobility is a new threat vector in the extended network. It’s particularly complex to secure and manage when tablets and smartphones are used for both personal and business needs. The Ponemon 2014 Security Impact of Mobile Device Use by Employees study notes that 66 percent of users download mobile apps without their company’s permission. This downloading behavior increases the attack surface by introducing unapproved or personal mobile applications.

As highlighted in the Cisco Annual Security Report for 2015, mobile applications are a new threat vector that could include malware. The potential for this user-appropriated malware to access corporate resources introduces a lot of new risks that need to be addressed by IT security personnel. At Cisco, we’ve just completed a new integration with Samsung to enable workers to be productive while locking down this expanded attack surface.

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