Today, Talos is publishing a glimpse into the most prevalent threats we've observed between Aug. 16 and Aug. 23. As with previous roundups, this post isn't meant to be an in-depth analysis. Instead, this post will summarize the threats we've observed by highlighting key behavioral characteristics, indicators of compromise, and discussing how our customers are automatically protected from these threats.
As a reminder, the information provided for the following threats in this post is non-exhaustive and current as of the date of publication. Additionally, please keep in mind that IOC searching is only one part of threat hunting. Spotting a single IOC does not necessarily indicate maliciousness. Detection and coverage for the following threats is subject to updates, pending additional threat or vulnerability analysis. For the most current information, please refer to your Firepower Management Center, Snort.org, or ClamAV.net.
For each threat described below, this blog post only lists 25 of the associated file hashes and up to 25 IOCs for each category. An accompanying JSON file can be found here that includes the complete list of file hashes, as well as all other IOCs from this post. As always, please remember that all IOCs contained in this document are indicators, and one single IOC does not indicated maliciousness. The most prevalent threats highlighted in this roundup are:
Tofsee is multipurpose malware that features a number of modules used to carry out various activities, such as sending spam messages, conducting click fraud, mining cryptocurrency, and more. Infected systems become part of the Tofsee spam botnet and are used to send large volumes of spam messages in an effort to infect additional systems and increase the overall size of the botnet under the operator’s control.
Neshta is file-infecting malware that also collects sensitive information from an infected machine and sends it to a C2 server.
Razy is oftentimes a generic detection name for a Windows trojan. It collects sensitive information from the infected host and encrypt the data, and send it to a command and control (C2) server. Information collected might include screenshots. The samples modify auto-execute functionality by setting and creating a value in the registry for persistence.
Elkern is a worm that spreads via peer-to-peer networks by masquerading as popular movies, games, or software. Once executed, it installs follow-on malware onto the system.
This cluster provides generic detection for the Dridex banking trojan that's downloaded onto a target's machine.
Vobfus is a worm that copies itself to external drives and attempts to gain automatic code execution via autorun.inf files. It also modifies the registry so that it will launch when the system is booted. Once installed, it attempts to download follow-on malware from its C2 server.
Indicators of Compromise
Value Name: Config1
Value Name: Config3
Value Name: Config0
Value Name: Config1
Value Name: Config2
Exploit Prevention Cisco AMP for Endpoints protects users from a variety of malware functions with exploit prevention. Exploit prevention helps users defend endpoints from memory attacks commonly used by obfuscated malware and exploits. These exploits use certain features to bypass typical anti-virus software, but were blocked by AMP thanks to its advanced scanning capabilities, even protecting against zero-day vulnerabilities.
Madshi injection detected - (1156)
Madshi is a code injection framework that uses process injection to start a new thread if other methods to start a thread within a process fail. This framework is used by a number of security solutions. It is also possible for malware to use this technique.
CVE-2019-0708 detected - (1075)
An attempt to exploit CVE-2019-0708 has been detected. The vulnerability, dubbed BlueKeep, is a heap memory corruption which can be triggered by sending a specially crafted Remote Desktop Protocol (RDP request). Since this vulnerability can be triggered without authentication and allows remote code execution, it can be used by worms to spread automatically without human interaction.
Kovter injection detected - (580)
A process was injected into, most likely by an existing Kovter infection. Kovter is a click fraud Trojan that can also act as an information stealer. Kovter is also file-less malware meaning the malicious DLL is stored inside Windows registry and injected directly into memory using PowerShell. It can detect and report the usage of monitoring software such as wireshark and sandboxes to its C2. It spreads through malicious advertising and spam campaigns.
Process hollowing detected - (526)
Process hollowing is a technique used by some programs to avoid static analysis. In typical usage, a process is started and its obfuscated or encrypted contents are unpacked into memory. The parent then manually sets up the first stages of launching a child process, but before launching it, the memory is cleared and filled in with the memory from the parent instead.
Dealply adware detected - (244)
DealPly is adware, which claims to improve your online shopping experience. It is often bundled into other legitimate installers and is difficult to uninstall. It creates pop-up advertisements and injects advertisements on webpages. Adware has also been known to download and install malware.
Excessively long PowerShell command detected - (214)
A PowerShell command with a very long command line argument that may indicate an obfuscated script has been detected. PowerShell is an extensible Windows scripting language present on all versions of Windows. Malware authors use PowerShell in an attempt to evade security software or other monitoring that is not tuned to detect PowerShell based threats.
Gamarue malware detected - (53)
Gamarue is a family of malware that can download files and steal information from an infected system. Worm variants of the Gamarue family may spread by infecting USB drives or portable hard disks that have been plugged into a compromised system.
Installcore adware detected - (34)
Install core is an installer which bundles legitimate applications with offers for additional third-party applications that may be unwanted. The unwanted applications are often adware that display advertising in the form of popups or by injecting into browsers and adding or altering advertisements on webpages. Adware is known to sometimes download and install malware.
Atom Bombing code injection technique detected - (25)
A process created a suspicious Atom, which is indicative of a known process injection technique called Atom Bombing. Atoms are Windows identifiers that associate a string with a 16-bit integer. These Atoms are accessible across processes when placed in the global Atom table. Malware exploits this by placing shell code as a global Atom, then accessing it through an Asynchronous Process Call (APC). A target process runs the APC function, which loads and runs the shellcode. The
malware family Dridex is known to use Atom Bombing, but other threats may leverage it as well.
PowerShell file-less infection detected - (15)
A PowerShell command was stored in an environment variable and run. The environment variable is commonly set by a previously run script and is used as a means of evasion. This behavior is a known tactic of the Kovter and Poweliks malware families.