Cisco Threat Research Blog

Threat intelligence for Cisco Products

We detect, analyze, and protect customers from both known and unknown emerging threats

New IDA Pro plugin provides TileGX support

Cisco Talos has a new plugin available for IDA Pro that provides a new disassembler for TileGX binaries. This tool should assist researchers in reverse-engineering threats in IDA Pro that target TileGX.

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Threat Roundup for September 27 to October 4

Today, Talos is publishing a glimpse into the most prevalent threats we’ve observed between Sep. 27 to Oct 4. 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.

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Reference:

TRU10042019 – This is a JSON file that includes the IOCs referenced in this post, as well as all hashes associated with the cluster. The list is limited to 25 hashes in this blog post. As always, please remember that all IOCs contained in this document are indicators, and that one single IOC does not indicate maliciousness. See the Read More link above for more details.

Open Document format creates twist in maldoc landscape

By Warren Mercer and Paul Rascagneres.

Introduction

Cisco Talos recently observed attackers changing the file formats they use in an attempt to thwart common antivirus engines. This can happen across other file formats, but today, we are showing a change of approach for an actor who has deemed antivirus engines perhaps “too good” at detecting macro-based infection vectors.  We’ve noticed that the OpenDocument (ODT) file format for some Office applications can be used to bypass these detections. ODT is a ZIP archive with XML-based files used by Microsoft Office, as well as the comparable Apache OpenOffice and LibreOffice software.

There have recently been multiple malware campaigns using this file type that are able to avoid antivirus detection, due to the fact that these engines view ODT files as standard archives and don’t apply the same rules it normally would for an Office document. We also identified several sandboxes that fail to analyze ODT documents, as it is considered an archive, and the sandbox won’t open the document as a Microsoft Office file. Because of this, an attacker can use ODT files to deliver malware that would normally get blocked by traditional antivirus software.

We only found a few samples where this file format was used. The majority of these campaigns using malicious documents still rely on the Microsoft Office file format, but these cases show that the ODT file format could be used in the future at a more successful rate. In this blog post, we’ll walk through three cases of OpenDocument usage. The two first cases targets Microsoft Office, while the third one targets only OpenOffice and LibreOffice users. We do not know at this time if these samples were used simply for testing or a more malicious context.

Read more at Talosintelligence.com

Threat Roundup for September 20 to September 27

Today, Talos is publishing a glimpse into the most prevalent threats we’ve observed between Sep. 20 to Sep 27. 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.

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Reference:

TRU272019 – This is a JSON file that includes the IOCs referenced in this post, as well as all hashes associated with the cluster. The list is limited to 25 hashes in this blog post. As always, please remember that all IOCs contained in this document are indicators, and that one single IOC does not indicate maliciousness. See the Read More link above for more details.

Divergent: “Fileless” NodeJS Malware Burrows Deep Within the Host

Executive summary

Cisco Talos recently discovered a new malware loader being used to deliver and infect systems with a previously undocumented malware payload called “Divergent.” We first dove into this malware after we saw compelling data from Cisco Advanced Malware Protection’s (AMP) Exploit Prevention.

This threat uses NodeJS — a program that executes JavaScript outside of a web browser — as well as the legitimate open-source utility WinDivert to facilitate some of the functionality in the Divergent malware. The use of NodeJS is not something commonly seen across malware families.

The observed malware campaigns associated with Divergent feature the use of persistence techniques most commonly associated with “fileless” malware, leaving behind few artifacts for researchers to look at. This malware can be leveraged by an attacker to target corporate networks and appears to be primarily designed to conduct click fraud. It also features several characteristics that have been observed in other click-fraud malware, such as Kovter.

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How Tortoiseshell created a fake veteran hiring website to host malware

Cisco Talos recently discovered a threat actor attempting to take advantage of Americans who may be seeking a job, especially military veterans. The actor, previously identified by Symantec as Tortoiseshell, deployed a website called hxxp://hiremilitaryheroes[.]com that posed as a website to help U.S. military veterans find jobs. The URL is strikingly close to the legitimate service from the U.S. Chamber of Commerce, https://www.hiringourheroes.org. The site prompted users to download an app, which was actually a malware downloader, deploying malicious spying tools and other malware.

This is just the latest actions by Tortoiseshell. Previous research showed that the actor was behind an attacker on an IT provider in Saudi Arabia. For this campaign Talos tracked, Tortoiseshell used the same backdoor that it has in the past, showing that they are relying on some of the same tactics, techniques and procedures (TTPs).

Read more at Talosintelligence.com

Threat Roundup for September 13 to September 20

Today, Talos is publishing a glimpse into the most prevalent threats we’ve observed between Sep. 13 to Sep 20. 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.

Read More

Reference:

TRU09202019 – This is a JSON file that includes the IOCs referenced in this post, as well as all hashes associated with the cluster. The list is limited to 25 hashes in this blog post. As always, please remember that all IOCs contained in this document are indicators, and that one single IOC does not indicate maliciousness. See the Read More link above for more details.

Emotet is back after a summer break

This blog post was written by Colin GradyWilliam Largent, and Jaeson Schultz.

Emotet is still evolving, five years after its debut as a banking trojan. It is one of the world’s most dangerous botnets and malware droppers-for-hire. The malware payloads dropped by Emotet serve to more fully monetize their attacks, and often include additional banking trojans, information stealers, email harvesters, self-propagation mechanisms and even ransomware.

At the beginning of June 2019, Emotet’s operators decided to take an extended summer vacation. Even the command and control (C2) activities saw a major pause in activity. However, as summer begins drawing to a close, Talos and other researchers started to see increased activity in Emotet’s C2 infrastructure. And as of Sept. 16, 2019, the Emotet botnet has fully reawakened, and has resumed spamming operations once again. While this reemergence may have many users scared, Talos’ traditional Emotet coverage and protection remains the same. We have a slew of new IOCs to help protect users from this latest push, but past Snort coverage will still block this malware, as well traditional best security practices such as avoiding opening suspicious email attachments and using strong passwords.

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Cryptocurrency miners aren’t dead yet: Documenting the voracious but simple “Panda”

By Christopher Evans and David Liebenberg.

Executive summary

A new threat actor named “Panda” has generated thousands of dollars worth of the Monero cryptocurrency through the use of remote access tools (RATs) and illicit cryptocurrency-mining malware. This is far from the most sophisticated actor we’ve ever seen, but it still has been one of the most active attackers we’ve seen in Cisco Talos threat trap data. Panda’s willingness to persistently exploit vulnerable web applications worldwide, their tools allowing them to traverse throughout networks, and their use of RATs, means that organizations worldwide are at risk of having their system resources misused for mining purposes or worse, such as exfiltration of valuable information.

Panda has shown time and again they will update their infrastructure and exploits on the fly as security researchers publicize indicators of compromises and proof of concepts. Our threat traps show that Panda uses exploits previously used by Shadow Brokers — a group infamous for publishing information from the National Security Agency — and Mimikatz, an open-source credential-dumping program.

Talos first became aware of Panda in the summer of 2018, when they were engaging in the successful and widespread “MassMiner” campaign. Shortly thereafter, we linked Panda to another widespread illicit mining campaign with a different set of command and control (C2) servers. Since then, this actor has updated its infrastructure, exploits and payloads. We believe Panda is a legitimate threat capable of spreading cryptocurrency miners that can use up valuable computing resources and slow down networks and systems. Talos confirmed that organizations in the banking, healthcare, transportation, telecommunications, IT services industries were affected in these campaigns.

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