Microsoft Patch Tuesday for March 2026 — Snort rules and prominent vulnerabilities

Microsoft has released its monthly security update for March 2026 which includes 79 vulnerabilities, including three that Microsoft marked as "critical." The remaining vulnerabilities listed are classified as "important." Microsoft assessed that exploitation of the three "critical" vulnerabilitie...

UAT-8837 targets critical infrastructure sectors in North America

Cisco Talos is closely tracking UAT-8837, a threat actor we assess with medium confidence is a China-nexus advanced persistent threat APT actor based on overlaps in tactics, techniques, and procedures TTPs with those of other known China-nexus threat actors. Based on UAT-8837's TTPs and...

Trick, treat, repeat

Welcome to this week's edition of the Threat Source newsletter. This one is pretty much an updated, Halloween-themed version of my newsletter from July, including data up through Q3. October 14th has passed, so free support for Windows 10 has come to an end, leaving you with no more fixes unless...

Everyone's on the cyber target list

Welcome to this week's edition of the Threat Source newsletter. I've discovered that being a rent guarantor for someone is an involved experience. While I'm glad that I can help out a loved one secure a better rental property, the process of verifying my identity and ability to cover any missed...

Ghosted by a cybercriminal

Welcome to this week's edition of the Threat Source newsletter. Talos recently published research into how threat actors are increasingly teaming up across the attack chain. Each group handles a slice of the operation, passing the breach along like a relay baton. It's a concerning trend -- one th...

State-of-the-art phishing: MFA bypass

Cybercriminals are bypassing multi-factor authentication MFA using adversary-in-the-middle AiTM attacks via reverse proxies, intercepting credentials and authentication cookies. The developers behind Phishing-as-a-Service PhaaS kits like Tycoon 2FA and Evilproxy have added features to make them...

Care what you share

Welcome to this week's edition of the Threat Source newsletter. As we navigate our daily routines, certain tasks become second nature to us, especially if they are integral to our professions. However, what feels instinctive to one person might be foreign to another. This disparity is akin to a...

Year in Review: Key vulnerabilities, tools, and shifts in attacker email tactics

Over the next few weeks, we're breaking down the most critical sections of our 2024 Year in Review. This week, we examine the most frequently targeted vulnerabilities--particularly those affecting network infrastructure. We also detail a noticeable shift in adversary behavior, as threat actors mo...

Year in Review: In conversation with the report's authors

🎥 Talos Year in Review 2024: Part 1 & 2 - Watch Now! Another year, another mountain of malicious telemetry to sift through. I spoke with a few of Talos' Year in Review authors, freshly out of the sandbox, to discuss the how's and why's of our biggest findings. 👉 Part 1: The major theme of 2024, t...

Available now: 2024 Year in Review

Welcome to Cisco Talos' 2024 Year in Review, available for download now. This report is powered by threat telemetry from over 46 million global devices across 193 countries and regions, amounting to more than 886 billion security events per day. Explore key insights in topics including the top...

UAT-5918 targets critical infrastructure entities in Taiwan

By Jung soo An, Asheer Malhotra, Brandon White, and Vitor Ventura. Cisco Talos discovered a malicious campaign we track under the UAT-5918 umbrella that has been active since at least 2023. UAT-5918, a threat actor believed to be motivated by establishing long-term access for information theft,...

Writing a BugSleep C2 server and detecting its traffic with Snort

In June 2024, security researchers published their analysis of a novel implant dubbed "MuddyRot"aka "BugSleep". This remote access tool RAT gives operators reverse shell and file input/output I/O capabilities on a victim's endpoint using a bespoke command and control C2 protocol. This blog will...

Are hardware supply chain attacks “cyber attacks?”

The recent attacks in the Middle East triggering explosions on pagers has raised new fears around physical hardware supply chain attacks. In cybersecurity, we typically consider supply chain attacks to target software, in which adversaries infect a legitimate tool with a malicious, fake update th...

A refresher on Talos’ open-source tools and the importance of the open-source community

Open-source software that is free to download, deploy and modify is a vital component in the fight for cyber security. Freely available software not only helps defend systems that would otherwise be unprotected, but it also allows people to learn and develop vital cybersecurity skills. In this...

The top stories coming out of the Black Hat cybersecurity conference

Over the next two weeks, two of the largest cybersecurity conferences in the world will take place in Las Vegas: Black Hat and DEF CON. That means product announcements, buzzwords and stories about "X smart appliance could burn your house down!" or something like that. Over the next two weeks, Il...

What is the dark web?

Most users interact with the internet through the web, and many of the threat actors we write about operate on the "dark web." Broadly speaking, the dark web is a small portion of the "deep web," where the deep web represents most of the Web. We know, its confusing -- lets walk through an example...

Adversaries increasingly using vendor and contractor accounts to infiltrate networks

Cisco Talos Incident Response Talos IR has repeatedly observed attackers targeting and using compromised vendor and contractor accounts VCAs during recent emergency response engagements. While high-profile software supply chain compromise events garner significant media attention e.g., the recent...

Researcher Spotlight: Jacob Finn creates his own public-private partnership at Talos

After working in government for several years, this Talos threat hunter is diving into the dark web Growing up, Jacob Finn says he wanted to be a detective or maybe a veterinarian, but theres still plenty of time for that. Today with Talos, hes a detective. And while hes still hunting for bad...

Video: Everything you need to know about ongoing state-sponsored attacks targeting network infrastructure across the globe

Cisco and Talos are continuing to track and research a series of ongoing cyber attacks and espionage targeting out-of-date and unpatched network hardware. In this video, Hazel Burton interviews Matt Olney and J.J. Cummings from Talos to discuss the "Jaguar Tooth" campaign the U.K. government and...

Threat Round up for January 6 to January 13

Today, Talos is publishing a glimpse into the most prevalent threats weve observed between Jan. 6 and Jan. 13. As with previous roundups, this post isnt meant to be an in-depth analysis. Instead, this post will summarize the threats weve observed by highlighting key behavioral characteristics,...

Video: How propaganda can spread on social media via memes, fake news

Cisco Talos is well-known for its work in spotting and defeating fake news, disinformation and misinformation. And state-sponsored actors, unwitting social media users and even direct government agencies have played a part in spreading fake news during Russia's invasion of Ukraine. In this video,...

What’s with the shared VBA code between Transparent Tribe and other threat actors?

By Vanja Svajcer and Vitor Ventura. Recently, we've been researching several threat actors operating in South Asia: Transparent Tribe, SideCopy, etc., that deploy a range of remote access trojans RATs. After a hunting session in our malware sample repositories and VirusTotal while looking into...

Threat Roundup for January 21 to January 28

Today, Talos is publishing a glimpse into the most prevalent threats we've observed between Jan. 21 and Jan. 28. 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...

Magnat campaigns use malvertising to deliver information stealer, backdoor and malicious Chrome extension

By Tiago Pereira. Talos recently observed a malicious campaign offering fake installers of popular software as bait to get users to execute malware on their systems. This campaign includes a set of malware distribution campaigns that started in late 2018 and have targeted mainly Canada, along...

Threat Roundup for October 22 to October 29

Today, Talos is publishing a glimpse into the most prevalent threats we've observed between Oct. 22 and Oct. 29. 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...

Threat Source newsletter (Oct. 14, 2021)

Newsletter compiled by Jon Munshaw.Good afternoon, Talos readers. It's still Cybersecurity Awareness Month, and what better way to celebrate by patching and then patching some more? This week was Microsoft Patch Tuesday, which only included two critical vulnerabilities, but still... This is only...

Vulnerability Spotlight: Use-after-free vulnerability in Microsoft Excel could lead to code execution

Marcin “Icewall” Noga of Cisco Talos discovered this vulnerability. Blog by Jon Munshaw. Cisco Talos recently discovered a use-after-free vulnerability in the ConditionalFormatting functionality of Microsoft Office Excel 2019 that could allow an attacker to execute arbitrary code on the... This i...

Threat Source newsletter (Sept. 16, 2021)

Newsletter compiled by Jon Munshaw.Good afternoon, Talos readers. It's a bird, it's a plane, it's a rat! We've been tracking a series of trojans targeting the aviation industry, and trying to lure victims in by sending them spam related to flight itineraries and other transportation... This is on...

Vulnerability Spotlight: Code execution vulnerability in Nitro Pro PDF

A Cisco Talos team member discovered these vulnerabilities. Blog by Jon Munshaw. Cisco Talos recently discovered a vulnerability in the Nitro Pro PDF reader that could allow an attacker to execute code in the context of the application. Nitro Pro PDF is part of Nitro Software’s... This is only th...

Threat Roundup for September 3 to September 10

Today, Talos is publishing a glimpse into the most prevalent threats we've observed between Sept. 3 and Sept. 10. 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...

Vulnerability Spotlight: Heap buffer overflow vulnerability in Ribbonsoft dxflib library

Lilith of Cisco Talos discovered this vulnerability. Blog by Jon Munshaw. Cisco Talos recently discovered an exploitable heap-based buffer overflow vulnerability in Ribbonsoft’s dxflib library that could lead to code execution. The dxflib library is a C++ library utilized by... This is only the...

Cheating the cheater: How adversaries are using backdoored video game cheat engines and modding tools

By Nick Lister and Holger Unterbrink, with contributions from Vanja Svajcer. News summary Cisco Talos recently discovered a new campaign targeting video game players and other PC modders.Talos detected a new cryptor used in several different malware campaigns hidden in seemingly legitimate files...

Microsoft Patch Tuesday for March 2021 — Snort rules and prominent vulnerabilities

By Jon Munshaw, with contributions from Nick Biasini. Microsoft released its monthly security update Tuesday, disclosing 89 vulnerabilities across its suite of products, the most in any month so far this year. There are 14 critical vulnerabilities as part of this release and one considered of “lo...

Vulnerability Spotlight: Memory corruption vulnerability in Accusoft ImageGear

Emmanuel Tacheau discovered this vulnerability. Blog by Jon Munshaw. Accusoft ImageGear contains a vulnerability that could allow an attacker to corrupt the software's memory, potentially allowing them to execute arbitrary code on the victim machine. The ImageGear library is a document-imaging...

Back from vacation: Analyzing Emotet’s activity in 2020

By Nick Biasini, Edmund Brumaghin, and Jaeson Schultz. Emotet is one of the most heavily distributed malware families today. Cisco Talos observes large quantities of Emotet emails being sent to individuals and organizations around the world on an almost daily basis. These emails are typically sen...

Microsoft Patch Tuesday for Nov. 2020 — Snort rules and prominent vulnerabilities

By Jon Munshaw, with contributions from Joe Marshall. Microsoft released its monthly security update Tuesday, disclosing just over 110 vulnerabilities across its products. This is a slight jump from last month when Microsoft disclosed one of their lowest vulnerability totals in months. Eighteen o...

Vulnerability Spotlight: Multiple JavaScript vulnerabilities in Adobe Acrobat Reader

Aleksandar Nikolic of Cisco Talos discovered these vulnerabilities. Blog by Joe Marshall Cisco Talos recently discovered an heap buffer overflow and a use after free vulnerability in Adobe Acrobat Reader. Adobe Acrobat Reader is one of the most popular and feature-rich PDF readers on the market. ...

Beers with Talos Ep. #93: “More Secure” myths and misconceptions

Beers with Talos BWT Podcast episode No. 93 is now available. Download this episode and subscribe to Beers with Talos:Apple Podcasts Google PodcastsSpotify StitcherIf iTunes and Google Play aren't your thing, click here. By Mitch Neff. Recorded Sept. 11, 2020 On today’s show, we take several of t...

LodaRAT Update: Alive and Well

By Chris Neal. During our continuous monitoring of LodaRAT, Cisco Talos observed changes in the threat that add new functionality. Multiple new versions of LodaRAT have been spotted being used in the wild.These new versions of LodaRAT abandoned their previous obfuscation techniques.Direct...

Threat Source newsletter for Aug. 27, 2020

Newsletter compiled by Jon Munshaw. Good afternoon, Talos readers. As part of our continued look at election security ahead of the November election, we have another research paper out this week. This time, we’re taking a closer look at disinformation campaigns, popularly known as “fake news.” Th...

Threat Source newsletter for Aug. 20, 2020

Newsletter compiled by Jon Munshaw. Good afternoon, Talos readers. Hactivism always seems to cool and noble in the movies. Video games and TV shows have no shortage of their “hacker heroes,” too. But what are the real-world consequences of users who release sensitive information or carry out data...

Threat Roundup for July 24 to July 31

Today, Talos is publishing a glimpse into the most prevalent threats we've observed between July 24 and July 31. 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...

Threat Source newsletter for July 16, 2020

Newsletter compiled by Jon Munshaw. Good afternoon, Talos readers. If you haven’t already, we highly recommend you read our in-depth research paper on election security. This paper represents four years of hands-on research, interviews and insight into how things have changed since 2016, and what...

Threat Roundup for July 3 to July 10

Today, Talos is publishing a glimpse into the most prevalent threats we've observed between July 3 and July 10. 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,...

Vulnerability Spotlight: Google Chrome PDFium memory corruption vulnerability

Aleksandar Nikolic of Cisco Talos discovered this vulnerability. Blog by Jon Munshaw. The PDF renderer inside Google Chrome, known as PDFium, contains a memory corruption vulnerability that could be exploited by an adversary. PDFium is open-source software that is utilized in the Chrome browser a...

Wipers - Destruction as a means to an end

This whitepaper post is authored by Vitor Ventura and with contributions from Martin Lee In a digital era when everything and everyone is connected, malicious actors have the perfect space to perform their activities. During the past few years, organizations have suffered several kinds of attacks...

BWT EP5 - It Has Been 0-days Since This Term was Abused

Beers with Talos Episode 5 "It Has Been 0-days Since This Term was Abused" is now availableListen here:Listen via iTunesListen directly on the Talos Podcasts page.Episode Notes:The crew talks about the potential of Samba echoing WannaCry and blocking SMB ports but you already did that, RIGHT?. We...

Ransomware incidents in Japan in the first half of 2026: Investigation of The Gentlemen’s infrastructure and evidence of Qilin's AI use

Compared with the same period last year, ransomware incidents in Japan increased slightly by approximately 4.7%, indicating that ransomware continues to pose a significant threat. In Japan, The Gentlemen was the most active ransomware group in the first half of 2026. Attackers continue to primari...

Microsoft Patch Tuesday for August 2026 — Snort rules and prominent vulnerabilities

Microsoft has released its monthly security update for August 2026, which includes 421 vulnerabilities affecting a range of products, including 62 that Microsoft marked as "critical." Microsoft notes that 1 of the vulnerabilities disclosed this month have been exploited in the wild CVE-2026-68820...

The serpent’s tongue: Luring the Python out of its den

Python's popularity, readable syntax, and extensive third-party library ecosystem make it an attractive target for threat actors seeking to compromise developer devices and infrastructure. Malicious packages and supply-chain attacks are increasingly common, exploiting the trust built into Python'...