Dark Reading is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them.Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

IoT/Embedded Security //

Botnet

11/15/2018
09:35 AM
Scott Ferguson
Scott Ferguson
News Analysis-Security Now
50%
50%

Mylobot Botnet & Khalesi Malware Deliver One-Two Security Punch

The recently discovered Mylobot botnet is now delivering Khalesi information stealer malware as part of its payload, according to new research from CenturyLink.

Mylobot, a recently discovered botnet that can elude antivirus software and sandboxes, is now able to deliver Khalesi information stealer malware on infected machines as part of a secondary attack, according to new research from CenturyLink.

In June, researchers at Deep Instinct fist took notice of Mylobot -- it's named after a family pet -- as a new type of sophisticated botnet that include anti-virtual machine and anti-sandboxing techniques to help avoid detection. Additionally, the malware has the ability wait dormant for as long as two weeks before it contacts the command-and-control (C&C) server.

As part of the attack, the botnet can block ports on the network firewall, and also has the ability to disable Windows Defender and Windows Update to ensure that its activity can continue once it has infected a machine.

However, it's the botnet's ability to deliver additional payloads once a machine is infected that is the most troubling.

Now, CenturyLink has found Mylobot delivering Khalesi as one of those payloads to create a secondary attack. Researchers have been tracking the botnet by looking at IPs extracted from the firm's honeypot logs and combining that with DNS resolution data.

CenturyLink has been blocking Mylobot within its network and alerting customers, however, researchers have been finding infected IPs in Iraq, Iran, Argentina, Russia, Vietnam, China, India, Saudi Arabia, Chile and Egypt, according to a November 14 blog post.

Overall, CenturyLink found 18,000 unique IPs communicating with Mylobot's C&C server.

Further analysis of the communication between the botnet and the C&C server found that two files were being downloaded and these contained specific executables. With help from Kaspersky Labs, CenturyLink identified these files as Khalesi malware.

Mike Benjamin, the head of CenturyLink's Threat Research Labs, notes that, so far, Mylobot is only delivering Khalesi, but that could change, and the botnet has the ability to download any number of payloads. It's not clear if the groups behind these different strains of malware are working together.

"We can describe Mylobot as the stage 1 infection of hosts that is then downloading stage 2, the Khalesi information stealer," Benjamin wrote in an email to Security Now. "We have seen the multi-stage infection behavior from a wide variety of actors and they typically fall into two camps: either the author wishes to allow their infected hosts to be used for a variety of their own future needs, so this modular nature of the technology allows them to deploy their own malice in the future, or the author aims to allow third parties to make use of their infected hosts by selling the botnet as a platform for others to consume."

While the motivation behind this scheme is not known, Khalesi is known to steal Khalesi usernames and passwords, as well as credit card information and can exfiltrate this data to cybercriminals for later use.

"During the time period we have been monitoring Mylobot, we have only seen it deliver Khalesi," Benjamin wrote. "However, what makes Mylobot so dangerous is its ability to download and execute any other type of payload the attacker wants."

Related posts:

— Scott Ferguson is the managing editor of Light Reading and the editor of Security Now. Follow him on Twitter @sferguson_LR.

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
COVID-19: Latest Security News & Commentary
Dark Reading Staff 9/25/2020
Hacking Yourself: Marie Moe and Pacemaker Security
Gary McGraw Ph.D., Co-founder Berryville Institute of Machine Learning,  9/21/2020
Startup Aims to Map and Track All the IT and Security Things
Kelly Jackson Higgins, Executive Editor at Dark Reading,  9/22/2020
Register for Dark Reading Newsletters
White Papers
Video
Cartoon
Current Issue
Special Report: Computing's New Normal
This special report examines how IT security organizations have adapted to the "new normal" of computing and what the long-term effects will be. Read it and get a unique set of perspectives on issues ranging from new threats & vulnerabilities as a result of remote working to how enterprise security strategy will be affected long term.
Flash Poll
How IT Security Organizations are Attacking the Cybersecurity Problem
How IT Security Organizations are Attacking the Cybersecurity Problem
The COVID-19 pandemic turned the world -- and enterprise computing -- on end. Here's a look at how cybersecurity teams are retrenching their defense strategies, rebuilding their teams, and selecting new technologies to stop the oncoming rise of online attacks.
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2020-15208
PUBLISHED: 2020-09-25
In tensorflow-lite before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, when determining the common dimension size of two tensors, TFLite uses a `DCHECK` which is no-op outside of debug compilation modes. Since the function always returns the dimension of the first tensor, malicious attackers can ...
CVE-2020-15209
PUBLISHED: 2020-09-25
In tensorflow-lite before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, a crafted TFLite model can force a node to have as input a tensor backed by a `nullptr` buffer. This can be achieved by changing a buffer index in the flatbuffer serialization to convert a read-only tensor to a read-write one....
CVE-2020-15210
PUBLISHED: 2020-09-25
In tensorflow-lite before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, if a TFLite saved model uses the same tensor as both input and output of an operator, then, depending on the operator, we can observe a segmentation fault or just memory corruption. We have patched the issue in d58c96946b and ...
CVE-2020-15211
PUBLISHED: 2020-09-25
In TensorFlow Lite before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, saved models in the flatbuffer format use a double indexing scheme: a model has a set of subgraphs, each subgraph has a set of operators and each operator has a set of input/output tensors. The flatbuffer format uses indices f...
CVE-2020-15212
PUBLISHED: 2020-09-25
In TensorFlow Lite before versions 2.2.1 and 2.3.1, models using segment sum can trigger writes outside of bounds of heap allocated buffers by inserting negative elements in the segment ids tensor. Users having access to `segment_ids_data` can alter `output_index` and then write to outside of `outpu...