Juniper Threat Labswas recently investigating and analyzing the resurgence of Troldesh ransomware and during our investigation, we gained a few insights into their operation. What we found is that the threat actors implemented a coordinated operation by using other modules to distribute their malware. They use a CMS bruteforcer module that is responsible for infecting loosely configured CMS sites that are used as download servers. They monetized their operation via ransomware and cryptomining. They also use TOR for all of their network communication to give them anonymity.
The advent of microservices has led to us witnessing containers take the cloud by storm. But, this boom in the container-cloud relationship is exposing security issues that are inviting malware into the party as well. Juniper Threat Labs recently discovered an infection in the wild that hunts for misconfigured publicly exposed Docker services in the cloud and infects them with containers that run Monero miners.
Deploying detection solutions on an endpoint host comes with constraints - limited availability of CPU, memory, disk and other resources, stability constraints, policy adherence and restrictions, the need to be non-intrusive to the user, the host OS and other applications on the host.
Juniper Threat Labs has been monitoring the activity of a botnet, which is now being referred to as ViroBot by TrendMicro in theirblog, and would like to share additional information that can provide insight into the TTP (techniques, tacticsandprocedure) of the threat actor. During our investigation, we also found a Unix keylogger related to this threat actor. The keylogger is a 64-bit ELF malware, and at the time of this writing, it has 0 hits on Virustotal. This blog shares technical aspects of both the Windows and Unix malware.
The Kronos banking malware family was first known to be sold in the underground market in 2014. It surfaced again in mid-2017 after being dormant for some time. Then, in April 2018 we saw a resurgence of Kronos in new avatar Orosis. Some security vendors reported its presence in September 2018.
Kronos Attack Vectors:
Kronos is known to be distributed via various attack vectors, some versions known to spread through malvertising. Some have also spread using phishing emails containing document attachments containing macros that can then download the malware. Some of the attachments are also known to exploit a Microsoft Word vulnerability CVE-2017-11882.
The initial versions of Kronos were known to use the well-known process hollowing technique. This is a technique frequently used by malware to impersonate legitimate processes. The malware launches a legitimate process and replaces the the code in runtime with a malicious payload. The latest version of this seems to use a new technique very similar to Doppelgänging already analysed in this Malwarebytes blog. The concept was described atBlack Hat 2017.
Technical Description of the Payload:
The malware creates a copy of itself into app data and maintains persistence by creating a run entry in the registry. HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
It uses a technique called Web-injects. Web Inject is a man-in-the-browser-attack, a technique by which malware can manipulate the web page in the browser and display a custom web page. As an example, if a banking website displays username and password in the login page, the malware can modify the web page on the client side to have an additional field to enter ATM pin. Thus the end user gets fooled into thinking that the the original bank site is asking for their ATM pin. This kind of attack is effective against sites using SSL encryption too as opposed to man-in-the-middle attacks which only work on unecrypted traffic (unless a malicious certificate is inserted in the browser and accepted by the user). Kronos web-injects are very similar to those of the infamous Zeus family.
The trojan is then modularized and uses a configuration file which makes it easier to update the malware.
malware uses config file with extension cfg
The configuration file is very much similar to Zeus. The configuration file has specifications of the web injects. It mentions what modifications (html code injections) need to be done to the web page of a certain banking website on the victim’s machine. The Zeus type of configuration file usually has strings like set_url,data_before,data_after,data_inject,data_end. These strings indicate fields in the configuration file. These fields tell where and what to be injected.
string related to zeus style config file
set_url field specifies the target URL
data_before and data_after are used to indicate the location in the web page when malicious code is injected
data_inject and data_end used enclose the content that needs to be injected
Some versions of Kronos are also known to steal and inject code into social networking sites.
Unpacked versions of Kronos can be identified easily as they have the “Kronos” string in them.
"Kronos" string in unpacked sample
Latest versions are known to use TOR network and also have VNC modules.
Both Juniper Sky ATP and Juniper ATP Appliance on-prem solutions detect this threat as seen in the screenshots below. Keeping security solutions up-to-date can keep the customer protected against this type of threat, as well as others.
On September 19, 2018, Juniper Threat Labs discovered a new wave of attacks from a cryptominer worm targeting Linux servers, home networking devices, and IOT devices. These attacks were bundled with a number of exploits to spread rapidly and widely. The attack has three parts: infection, mining, and spreading.