Cisco Threat Research Blog

The 1st of February, Adobe published an advisory concerning a Flash vulnerability (CVE-2018-4878). This vulnerability is a use after free that allows Remote Code Execute through a malformed Flash object. Additionally KISA (Korean CERT) published an advisory about a Flash 0-day used in the wild. Talos identified that an attacker exploited this vulnerability with a Flash object embedded in a Microsoft Excel document. By opening the document, the exploit was executed in order to download an additional payload from a compromised website.

Read More >>

The Dark Side of the Digital Gold Rush

This post was authored by Nick Biasini, Edmund Brumaghin, Warren Mercer and Josh Reynolds with contributions from Azim Khodijbaev and David Liebenberg.

Executive Summary

The threat landscape is constantly changing; over the last few years malware threat vectors, methods and payloads have rapidly evolved. Recently, as cryptocurrency values have exploded, mining related attacks have emerged as a primary interest for many attackers who are beginning to recognize that they can realize all of the financial upside of previous attacks, like ransomware, without needing to actually engage the victim and without the extraneous law enforcement attention that comes with ransomware attacks.

This focus on mining isn’t entirely surprising, considering that various cryptocurrencies along with “blockchain” have been all over the news as the value of these currencies has exponentially increased. Adversaries have taken note of these gains and have been creating new attacks that help them monetize this growth. Over the past several months Talos has observed a marked increase in the volume of cryptocurrency mining software being maliciously delivered to victims.

In this new business model, attackers are no longer penalizing victims for opening an attachment, or running a malicious script by taking systems hostage and demanding a ransom. Now attackers are actively leveraging the resources of infected systems for cryptocurrency mining. In these cases the better the performance and computing power of the targeted system, the better for the attacker from a revenue generation perspective. IoT devices, with their lack of monitoring and lack of day to day user engagement, are fast becoming an attractive target for these attackers, as they offer processing power without direct victim oversight. While the computing resources within most IoT devices are generally limited, the number of exposed devices that are vulnerable to publicly available exploits is high which may make them attractive to cyber criminals moving forward.

To put the financial gains in perspective, an average system would likely generate about $0.25 of Monero per day, meaning that an adversary who has enlisted 2,000 victims (not a hard feat), could generate $500 per day or $182,500 per year. Talos has observed botnets consisting of millions of infected systems, which using our previous logic means that these systems could be leveraged to generate more than $100 million per year theoretically. It is important to note that due to volatility present across cryptocurrency markets, these values may change drastically from day to day. All calculations in this blog were made based on XMR/USD at the time of this writing.

Read More >>

2017 was an eventful year for cyber security with high profile vulnerabilities that allowed self-replicating worm attacks such as WannaCry and BadRabbit to impact organizations throughout the world. In 2017, Talos researchers discovered many new attacks including backdoors in legitimate software such as CCleaner, designed to target high tech companies as well as M.E.Doc, responsible for initial spread of Nyetya. Despite all those, headline making attacks are only a small part of the day to day protection provided by security systems.

In this post we review some of the findings created by investigating the most frequently triggered Snort signatures as reported by Cisco Meraki systems and included in the Snort default policy set.

Read more >>

This vulnerability was discovered by Tyler Bohan of Cisco Talos.

Executive Summary

Walt Disney PTEX is an open source software application maintained by Walt Disney Animation Studios. It is designed for use in post-production rendering. It allows for the storage of thousands of texture mappings within a single file. This particular software library is in many other software applications such as Pixar’s RenderMan, giving it a large install base. A list of other applications that have incorporated PTEX is available here. Talos has recently discovered a stack-based buffer overflow in PTEX that could potentially allow a remote attacker to execute arbitrary code on affected systems.

Read More >>

Introduction

Over the past five years the Necurs botnet has established itself as the largest purveyor of spam worldwide. Necurs is responsible for emailing massive amounts of banking malware, ransomware, dating spam, pump-n-dump stock scams, work from home schemes, and even cryptocurrency wallet credential phishing. Necurs sends so much spam that at times Necurs’ spam campaigns can make up more than 90% of the spam seen by Cisco Talos in one day.

To conduct a deeper analysis of Necurs, Talos extracted 32 distinct spam campaigns sent by Necurs between August 2017 and November 2017. The result was a collection of over 2.1 million spam messages, sent from almost 1.2 million distinct sending IP addresses in over 200 countries and territories.

Read More

Overview

Talos is disclosing a single NULL pointer dereference vulnerability in the tinysvcmdns library. Tinysvcmdns is a tiny MDNS responder implementation for publishing services. This is essentially a mini and embedded version of Avahi or Bonjour.

Read More >>

This blog post is authored by Warren Mercer and Paul Rascagneres and with contributions from Jungsoo An.

This article exposes the malicious activities of Group 123 during 2017. We assess with high confidence that Group 123 was responsible for the following six campaigns:

• “Golden Time” campaign.
• “Evil New Year” campaign.
• “Are you Happy?” campaign.
• “FreeMilk” campaign.
• “North Korean Human Rights” campaign.
• “Evil New Year 2018” campaign.

On January 2nd of 2018, the “Evil New Year 2018” was started. This campaign copies the approach of the 2017 “Evil New Year” campaign.

The links between the different campaigns include shared code and compiler artifacts such as PDB (Program DataBase) patterns which were present throughout these campaigns.

Based on our analysis, the “Golden Time”, both “Evil New Year” and the “North Korean Human Rights” campaigns specifically targeted South Korean users. The attackers used spear phishing emails combined with malicious HWP documents created using Hancom Hangul Office Suite. Group 123 has been known to use exploits (such as CVE-2013-0808) or scripting languages harnessing OLE objects. The purpose of the malicious documents was to install and to execute ROKRAT, a remote administration tool (RAT). On occasion the attackers directly included the ROKRAT payload in the malicious document and during other campaigns the attackers leveraged multi-stage infection processes: the document only contained a downloader designed to download ROKRAT from a compromised web server.

Additionally, the “FreeMilk” campaign targeted several non-Korean financial institutions. In this campaign, the attackers made use of a malicious Microsoft Office document, a deviation from their normal use of Hancom documents. This document exploited a newer vulnerability, CVE-2017-0199. Group 123 used this vulnerability less than one month after its public disclosure. During this campaign, the attackers used 2 different malicious binaries: PoohMilk and Freenki. PoohMilk exists only to launch Freenki. Freenki is used to gather information about the infected system and to download a subsequent stage payload. This malware was used in several campaigns in 2016 and has some code overlap with ROKRAT.

Finally, we identified a 6th campaign that is also linked to Group 123. We named this 6th campaign “Are You Happy?”. In this campaign, the attackers deployed a disk wiper. The purpose of this attack was not only to gain access to the remote infected systems but to also wipe the first sectors of the device. We identified that the wiper is a ROKRAT module.

Read More >>

Technology has evolved in incredible ways that has helped people to create and visualize media like never before. Today, people can use tools such as Blender to visualize, model, and animate 3D content, especially since it’s free and open-source software. However, this also make it an attractive target for adversaries to audit and find vulnerabilities. Given the user base of Blender, exploiting these vulnerabilities to compromise a user could have a significant impact as attackers could use the foothold gained by attacking Blender to further compromise an organization’s network.

Today, Talos is disclosing multiple vulnerabilities that have been identified in Blender. These vulnerabilities could allow an attacker to execute arbitrary code on an affected host running Blender. A user who opens a specially crafted file in Blender that is designed to trigger one of these vulnerabilities could be exploited and compromised.

Talos has responsibly disclosed these vulnerabilities to Blender in an attempt to ensure they are addressed. However, Blender has declined to address them stating that “fixing these issues one by one is also a waste of time.” As a result, there currently is no software update that addresses these vulnerabilities. Additionally, Blender developers believe that “opening a file with Blender should be considered like opening a file with the Python interpreter, you have [to trust] the source it is coming from.”

Read More >>