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Reversing Multilayer .NET Malware

This post was authored by Dave McDaniel with contributions from Jaeson Schultz

Recently, we came across a malware sample that has been traversing the Internet disguised as an image of a woman. The malware sample uses several layers of obfuscation to hide its payload, including the use of steganography. Steganography is the practice of concealing a message, image, or file within another message, image, or file. Steganography can be used in situations where encryption might bring unwanted attention. Encrypted traffic from an unusual source is going to draw unwanted attention. Steganography allows malicious payloads to hide in plain sight. It also allows the attacker to bypass security devices. In our sample malware, steganography is used to decrypt and execute a second dropper, which in turn installs a user-land rootkit to further hide its intentions. The rootkit adds another layer of obfuscation by installing a DarkComet backdoor, using RC4 encryption to encrypt its configuration settings and send data to its command and control server.

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Threat Spotlight: Group 72, Opening the ZxShell

This post was authored by Andrea Allievi, Douglas Goddard, Shaun Hurley, and Alain Zidouemba.

Recently, there was a blog post on the takedown of a botnet used by threat actor group known as Group 72 and their involvement in Operation SMN.  This group is sophisticated, well funded, and exclusively targets high profile organizations with high value intellectual property in the manufacturing, industrial, aerospace, defense, and media sector. The primary attack vectors are watering-hole, spear phishing, and other web-based attacks.

Frequently, a remote administration tool (RAT) is used to maintain persistence within a victim’s organization. These tools are used to further compromise the organization by attacking other hosts inside the targets network.

ZxShell (aka Sensocode) is a Remote Administration Tool (RAT) used by Group 72 to conduct cyber-espionage operations. Once the RAT is installed on the host it will be used to administer the client, exfiltrate data, or leverage the client as a pivot to attack an organization’s internal infrastructure.  Here is a short list of the types of tools included with ZxShell:

  • Keylogger (used to capture passwords and other interesting data)
  • Command line shell for remote administration
  • Remote desktop
  • Various network attack tools used to fingerprint and compromise other hosts on the network
  • Local user account creation tools

For a complete list of tools please see the MainConnectionIo section.

The following paper is a technical analysis on the functionality of ZxShell. The analysts involved were able to identify command and control (C2) servers, dropper and installation methods, means of persistence, and identify the attack tools that are core to the RAT’s purpose. In addition, the researchers used their analysis to provide detection coverage for Snort, Fireamp, and ClamAV.

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Threat Spotlight: Group 72

This post is co-authored by Joel Esler, Martin Lee and Craig Williams

Everyone has certain characteristics that can be recognised. This may be a way of walking, an accent, a turn of phrase or a style of dressing. If you know what to look for you can easily spot a friend or acquaintance in a crowd by knowing what characteristics to look for. Exactly the same is true for threat actors.

Each threat actor group may have certain characteristics that they display during their attack campaigns. These may be the types of malware that they use, a pattern in the naming conventions of their command and control servers, their choice of victims etc. Collecting attack data allows an observer to spot the characteristics that define each group and identify specific threat actors from the crowd of malicious activity on the internet.

Talos security and intelligence research group collects attack data from our various telemetry systems to analyse, identify and monitor threat actors through their different tactics, techniques, and procedures. Rather than give names to the different identified groups, we assign numbers to the threat actors. We frequently blog about significant attack campaigns that we discover, behind the scenes we integrate our intelligence data directly into our products. As part of our research we keep track of certain threat actor groups and their activities. In conjunction with a number of other security companies, we are taking action to highlight and disrupt the activities of the threat actors identified by us as Group 72. Read More »

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The Expanding Burden of Security

July 8, 2014 at 6:00 am PST

[ed. Note: This post was updated 7/9/2014 to include new information not available to the author at the time of original publishing]

I just returned from the Gartner Security Summit at the Gaylord Resort in National Harbor Maryland. Each morning I took my run along the Potomac River and passed this sculpture of a man buried in the sand.

KT_sandman

In speaking with many IT executives they expressed specific concerns around their IT security, and this sculpture of the “man in the sand” took on new meaning for me. I could see how they might similarly feel overwhelmed and buried given their limited resources and the abundance of threats to their environments. Yes, I’ve been in this industry too long! Anyway, throughout all of my conversations it was abundantly clear that people were looking for a new way to approach securing their networks and applications. Customers are recognizing that unsecured access to the network is a critical threat vector; however, when leveraged properly, the network itself also provides a significant platform that offers comprehensive protection to close those gaps. So, what do I mean by that?

The network uniformly sees and participates in everything across the threat continuum, whether before, during or after an attack. If we can leverage the insights and inherent control the network provides, IT organizations can truly augment their overall end-to-end security across this continuum. If done correctly, this augmentation can happen without investing a large amount of time, energy, and resources in filling all the gaps to secure their environments -- regardless of legacy network, endpoint, mobile, virtual, or cloud usage models

Cisco strongly believes that the network must work intimately with various security technologies in a continuous fashion to offer protection for networks, endpoints, virtual, data centers and mobile.

The New Security Model

Given Cisco’s breadth and depth of security, we did not have room to exhibit our networking devices. However, within much of our networking (and even security) offerings, we have embedded security capabilities that provide more comprehensive protection across the entire threat continuum.

An example of this is Cisco TrustSec embedded network access enforcement, which provides network segmentation based on highly differentiated access policies. Cisco TrustSec works with Cisco ISE to provide consistent secure access that is mapped to IT business goals. Cisco ISE and TrustSec are part of the Cisco Unified Access solution and leverage a superior level of context and simplified policy management across the entire infrastructure in order to ensure that the right users and devices gain the right access to the right resources at any given time.

Cisco’s integrated approach to security reduces complexity, while providing unmatched visibility, continuous control and advanced threat protection, which, in turn, allows customers to prioritize more efficiently and act more quickly - before, during, and after an attack. Through Cisco’s New Security Model, we help you achieve a more pleasant experience and get you dug out of the sand. To learn more and go beyond just a shovel and pail, go to Cisco’s Security Page.

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Executing on our Vision: Cisco’s Comprehensive Advanced Malware Protection

The increased scrutiny on security is being driven by the evolving trends of expanding networks, mobility, cloud computing and a threat landscape that is more dynamic than ever. A combination of these factors has led to an increase in attack access points and a re-definition of the traditional network perimeter.

Due to these concerns, we have been strong proponents of threat-centric security that lets defenders address the full attack continuum and all attack vectors to respond at any time — before, during, and after attacks.

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