Talos IR ransomware engagements and the significance of timeliness in incident response

Cisco Talos routinely responds to ransomware engagements where the impact could have been mitigated or wholly prevented if the victim organization had initiated remediation efforts earlier in the attack lifecycle. The significance of early intervention in ransomware attacks is particularly...

Patch, track, repeat

Welcome to this week's edition of the Threat Source newsletter. We've made it halfway through 2025 already! It's been a while since I last wrote about CVEs and how free support for Windows 10 will end on October 14, 2025, leaving you with no more security fixes. While the CVE system remains the...

Asus and Adobe vulnerabilities

Cisco Talos' Vulnerability Discovery & Research team recently disclosed two vulnerabilities each in Asus Armoury Crate and Adobe Acrobat products. The vulnerabilities mentioned in this blog post have been patched by their respective vendors, all in adherence to Cisco 's third-party vulnerability...

Microsoft Patch Tuesday for July 2025 — Snort rules and prominent vulnerabilities

Microsoft has released its monthly security update for July 2025, which includes 132 vulnerabilities affecting a range of products, including 14 that Microsoft marked as "critical." In this month's release, Microsoft observed none of the included vulnerabilities being actively exploited in the...

A message from Bruce the mechanical shark

Welcome to this week's edition of the Threat Source newsletter. Hi, I'm Bruce, the 25-foot mechanical star of "Jaws." This summer marks 50 years since my 4 minutes of screentime kept people out of the water for decades. Maybe this Fourth of July weekend you're planning to sea-shanty your way to a...

PDFs: Portable documents, or perfect deliveries for phish?

Cisco recently developed and released an update to its brand impersonation detection engine for emails. This new update enhances detection coverage and includes a wider range of brands that are delivered using PDF payloads or attachments. A significant portion of email threats with PDF payloads...

Getting a career in cybersecurity isn’t easy, but this can help

Welcome to this week's edition of the Threat Source newsletter. Happy summer, friends! I hope everyone is staying cool and/or warm. I am fresh back from an exhaustive but great time in San Diego at Cisco Live U.S. It was so good to see colleagues, meet new friends and pet many therapy dogs in the...

Decrement by one to rule them all: AsIO3.sys driver exploitation

Introduction Armoury Crate and AI Suite are applications used to manage and monitor ASUS motherboards and related components such as the processor, RAM or the increasingly popular RGB lighting. These types of applications often install drivers in the system, which are necessary for direct...

Cybercriminal abuse of large language models

Cybercriminals are continuing to explore artificial intelligence AI technologies such as large language models LLMs to aid in their criminal hacking activities. Some cybercriminals have resorted to using uncensored LLMs or even custom-built criminal LLMs for illicit purposes. Advertised features ...

A week with a "smart" car

Welcome to this week's edition of the Threat Source newsletter. June 9 was Whit Monday -- a bank holiday here in Germany -- so I decided to take the whole week off. It turned out to be the perfect opportunity to try out a brand new car. Little did I know, I was about to get a crash course in mode...

When legitimate tools go rogue

Late one Tuesday night, Elena's phone buzzed with an alert from her company's SIEM. Her team had set up a rule to flag when certain system tools -- whoami, nltest and nslookup--were run one after another in quick succession. That exact pattern had just triggered on a computer in the Finance...

Famous Chollima deploying Python version of GolangGhost RAT

In May 2025, Cisco Talos identified a Python-based remote access trojan RAT we call "PylangGhost," used exclusively by a North Korean-aligned threat actor. PylangGhost is functionally similar to the previously documented GolangGhost RAT, sharing many of the same capabilities. In recent campaigns,...

Know thyself, know thy environment

Welcome to this week's edition of the Threat Source newsletter. This week, I'm coming to you from Cisco Live in San Diego where I've just talked to a room that some of you may have been in, so writing this feels a bit surreal. It's really hard to try and write a cogent newsletter with all that's...

catdoc zero-day, NVIDIA, High-Logic FontCreator and Parallel vulnerabilities

Cisco Talos' Vulnerability Discovery & Research team recently disclosed three zero-day vulnerabilities in catdoc, as well as vulnerabilities in Parallel, NVIDIA and High-Logic FontCreator 15. The vulnerabilities mentioned in this blog post have been patched by their respective vendors, in adheren...

Microsoft Patch Tuesday for June 2025 — Snort rules and prominent vulnerabilities

Update 6/12/2025: Microsoft released an additional CVE CVE-2025-32717 . Details and SIDs have been reflected to include this additional vulnerability. Microsoft has released its monthly security update for June 2025, which includes 66 vulnerabilities affecting a range of products, including 10 th...

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...

Newly identified wiper malware “PathWiper” targets critical infrastructure in Ukraine

Cisco Talos observed a destructive attack on a critical infrastructure entity within Ukraine, using a previously unknown wiper we are calling "PathWiper". The attack was instrumented via a legitimate endpoint administration framework, indicating that the attackers likely had access to the...

A new author has appeared

Welcome to this week's edition of the Threat Source newsletter. In the words of Game Changer host Sam Reich, "And your host, me! I've been here the whole time!" Okay, maybe it's not the whole time, but for the past three months, I've been settling into my role here at Cisco Talos. Editing blogs,...

Cybercriminals camouflaging threats as AI tool installers

Cisco Talos has discovered new threats, including the ransomware CyberLock, LuckyGh0$t, and a newly-discovered malware we call "Numero," all of which masquerade as legitimate AI tool installers. CyberLock ransomware, developed using PowerShell, primarily focuses on encrypting specific files on th...

Scarcity signals: Are rare activities red flags?

By Darin Smith and John Arneson Cisco Talos reviewed six months of network connection telemetry logs spanning June 1, 2024 - Dec. 31, 2024, containing 3,220,829 log events and 742 unique base domains, to explore if domains that PowerShell rarely contacts are more likely to be malicious. Key...

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...

UAT-6382 exploits Cityworks zero-day vulnerability to deliver malware

Cisco Talos has observed exploitation of CVE-2025-0994, a remote-code-execution vulnerability in Cityworks, a popular asset management system. The Cybersecurity and Infrastructure Security Agency CISA and Trimble have both released advisories pertaining to this vulnerability, with Trimble's...

Duping Cloud Functions: An emerging serverless attack vector

Summary and background Google Cloud Platform GCP Cloud Functions are event-triggered, serverless functions that automatically scale and execute code in response to specific events like Hypertext Transfer Protocol HTTP requests or data changes. Tenable Research published an article discussing a...

Xoxo to Prague

Welcome to this week's edition of the Threat Source newsletter. I haven't been to Prague in a while, which is a pity. It's a wonderful city -- great people, amazing food. I've visited customers there, held team meetings at the local office shoutout to Petr! and spent some memorable summer days of...

Microsoft Patch Tuesday for May 2025 — Snort rules and prominent vulnerabilities

Microsoft has released its monthly security update for May of 2025 which includes 78 vulnerabilities affecting a range of products, including 11 that Microsoft marked as "critical". Microsoft noted five vulnerabilities that have been observed to be exploited in the wild. CVE-2025-30397 is a remot...

Defining a new methodology for modeling and tracking compartmentalized threats

In the evolving cyberthreat landscape, Cisco Talos is witnessing a significant shift towards compartmentalized attack kill chains, where distinct stages -- such as initial compromise and subsequent exploitation -- are executed by multiple threat actors. This trend complicates traditional threat...

Redefining IABs: Impacts of compartmentalization on threat tracking and modeling

Cisco Talos has observed a growing trend of attack kill chains being split into two stages -- initial compromise and subsequent exploitation -- executed by separate threat actors. This compartmentalization increases the complexity and difficulty of performing threat modeling and actor profiling...

The IT help desk kindly requests you read this newsletter

Welcome to this week's edition of the Threat Source newsletter. Authority bias is one of the many things that shape how we think. Taking the advice of someone with recognized authority is often far easier and usually leads to a better outcome than spending time and effort in researching the...

Spam campaign targeting Brazil abuses Remote Monitoring and Management tools

Cisco Talos identified a spam campaign targeting Brazilian users with commercial remote monitoring and management RMM tools since at least January 2025. Talos observed the use of PDQ Connect and N-able remote access tools in this campaign. The spam message uses the Brazilian electronic invoice...

Proactive threat hunting with Talos IR

At Cisco Talos, we understand that effective cybersecurity isn't just about responding to incidents -- it's about preventing them from happening in the first place. One of the most powerful ways we do this is through proactive threat hunting. Our Talos Incident Response Talos IR team works closel...

Understanding the challenges of securing an NGO

Welcome to this week's edition of the Threat Source newsletter. Recently, I was invited to sit on a panel at the CIO4Good Conference here in Washington D.C., where I talked about incident response and cyber preparedness to a room full of CIOs who help lead wonderful missions to help others. I'm...

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...

Year in Review: AI based threats

2024 wasn't the year that AI rewrote the cybercrime playbook -- but it did turbocharge some of the old tricks. In Cisco Talos' 2024 Year in Review, with the help of our friends at Robust Intelligence now a Cisco company, we dissect how cybercriminals used generative AI to scale up social...

IR Trends Q1 2025: Phishing soars as identity-based attacks persist

Phishing attacks spiked this quarter as threat actors leveraged this method of initial access in half of all engagements, a vast increase from previous quarters. Conversely, the use of valid accounts for initial access was rarely seen this quarter, despite being the top observed method in 2024,...

Lessons from Ted Lasso for cybersecurity success

Welcome to this week's edition of the Threat Source newsletter. "Be curious, not judgmental," Ted Lasso says, misattributing Walt Whitman. We forgive Ted because... well, he's Ted Lasso. If you've not watched the first season of Ted Lasso, there is a defining moment where Ted confronts a nefariou...

Introducing ToyMaker, an initial access broker working in cahoots with double extortion gangs

In 2023, Cisco Talos discovered an extensive compromise in a critical infrastructure enterprise consisting of a combination of threat actors. From initial access to double extortion, these actors slowly and steadily compromised a multitude of hosts in the network using a combination of various...

Year in Review: Attacks on identity and MFA

For our third focussed topic for Talos' 2024 Year in Review, we tell the story of how identity has become the pivot point for adversarial campaigns. The main themes of this story are credential abuse, Active Directory attacks, and MFA workarounds. Valid account usage was the 1 way attackers got i...

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...

Unmasking the new XorDDoS controller and infrastructure

Cisco Talos observed an existing distributed denial-of-service DDoS malware known as XorDDoS, continuing to spread globally between November 2023 and February 2025. A significant finding shows that over 70 percent of attacks using XorDDoS targeted the United States from Nov. 2023 to Feb. 2025. Th...

Eclipse and STMicroelectronics vulnerabilities

Cisco Talos' Vulnerability Discovery & Research team recently disclosed three vulnerabilities found in Eclipse ThreadX and four vulnerabilities in the STMicroelectronics fork of ThreadX called X-CUBE-AZRTOS. The vulnerabilities mentioned in this blog post have been patched by their respective...

Year in Review: The biggest trends in ransomware

This week, our Year in Review spotlight is on ransomware --where low-profile tactics led to high-impact consequences. Ransomware operators often prioritized stealth over complexity for initial access. They also focused on slipping past defenses with minimal noise--uninstalling security tools,...

Threat actors thrive in chaos

Welcome to this week's edition of the Threat Source newsletter. If there's one thing that threat actors love, it's chaos. Headlines in the news that provoke an emotional response make excellent phishing lures because the intense feelings invoked by a provocative subject line cause our critical...

Unraveling the U.S. toll road smishing scams

Cisco Talos has observed a widespread and ongoing financial theft SMS phishing smishing campaign since October 2024 that targets toll road users in the United States of America. We observed that the campaign targets people across several states in the U.S. according to the domain names used in th...

Microsoft Patch Tuesday for April 2025 — Snort rules and prominent vulnerabilities

Microsoft has released its monthly security update for April of 2025 which includes 126 vulnerabilities affecting a range of products, including 11 that Microsoft marked as "critical". In this month's release, none of the included vulnerabilities have been observed by Microsoft to be exploited in...

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...

One mighty fine-looking report

Welcome to this week's edition of the Threat Source newsletter. They say art is subjective, but have you ever seen a well-formatted bar chart? Van Gogh had Starry Night , but Talos' 2024 Year in Review available now! has color-coded data with perfect labels. True beauty. If you haven't yet had a...

Beers with Talos: Year in Review episode

Joe, Hazel, Bill and Dave break down Talos' Year in Review 2024 and discuss how and why cybercriminals have been leaning so heavily on attacks that are routed in stealth in simplicity. The team also provide insights into some of the topics of the report, including the top-targeted vulnerabilities...

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...

Gamaredon campaign abuses LNK files to distribute Remcos backdoor

Cisco Talos is actively tracking an ongoing campaign targeting users in Ukraine with malicious LNK files, which run a PowerShell downloader, since at least November 2024. The file names use Russian words related to the movement of troops in Ukraine as a lure. The PowerShell downloader contacts...