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.
As I’ve discussed in past blog posts, advanced malware and sophisticated attacks are relentless as they compromise environments using new and stealthy techniques. Modern malware is dynamic and exists in an interconnected ecosystem that is constantly in motion. It will use an array of attack vectors, take endless form factors, and launch attacks over time.
In contrast, most security tools today are stuck in time – a point in time to be exact. They scan files once at the point of entry to determine if they are malicious, letting the supposedly “good” files in, and kicking the known “bad” files out. If the malicious file isn’t caught at point of entry, or if it evolves and becomes malicious AFTER entering the environment, point-in-time detection technologies give us little recourse after an infection occurs.
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.
This post was written by Jaeson Schultz.
On October 14th information related to a new Windows vulnerability, CVE-2014-4114, was published. This new vulnerability affects all supported versions of Microsoft Windows. Windows XP, however, is not affected by this vulnerability. The problem lies in Windows’ OLE package manager. When triggered it allows for remote code execution.
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 »