State-sponsored actors, better known as the friends you don’t want

State-sponsored actors don't break in. They log in, and they use your own tools to stay invisible for months. Responding to a state-sponsored threat is nothing like responding to ransomware, and the differences can make or break the outcome. From logging and baselines to OT segmentation and suppl...

Unplug your way to better code

Welcome to this week's edition of the Threat Source newsletter. Hey, you. Yeah, you! The person endlessly scrolling or typing away at their computer. Did you touch grass today? It's just an expression, but if nature's your thing, that works just fine. What I do mean is that due to the nature of t...

The Trojan horse of cybercrime: Weaponizing SaaS notification pipelines

By Diana Brown Cisco Talos has recently observed an increase in activity that is leveraging notification pipelines in popular collaboration platforms to deliver spam and phishing emails. These emails are transmitted using the legitimate mail delivery infrastructure associated with GitHub and Jira...

Cybersecurity on a budget: Strategies for an economic downturn

During economic uncertainty, businesses face the challenge of maintaining strong cybersecurity while managing tightened budgets. Cyber threats can become more numerous, motivated, and persistent during economic downturns, making the need for resilient, cost-effective security measures critical...

What happened in Vegas (that you actually want to know about)

Welcome to this week's edition of the Threat Source newsletter. Last week I flew 5,000 miles to Las Vegas for Black Hat USA. After navigating the casino carpet labyrinth and finding the only venue in Nevada that serves a proper English breakfast tea with milk lifesaver, I've decided Black Hat fee...

IR Trends Q2 2025: Phishing attacks persist as actors leverage compromised valid accounts to enhance legitimacy

Phishing remained the top method of initial access this quarter, appearing in a third of all engagements - a decrease from 50 percent last quarter. Threat actors largely leveraged compromised internal or trusted business partner email accounts to deploy malicious emails, bypassing security contro...

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...

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...

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...

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...

Small praise for modern compilers - A case of Ubuntu printing vulnerability that wasn’t

By Aleksandar Nikolich Earlier this year, we conducted code audits of the macOS printing subsystem, which is heavily based on the open-source CUPS package. During this investigation, IPP-USB protocol caught our attention. IPP over USB specification defines how printers that are available over USB...

Find the helpers

Welcome to this week's edition of the Threat Source newsletter. "When I was a boy and I would see scary things in the news, my mother would say to me, 'Look for the helpers. You will always find people who are helping.'" ― Fred Rogers There's no world where following Mr. Roger's advice is wrong...

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...

Cisco Talos at RSAC 2024

With RSAC just a week away, Cisco Talos is gearing up for another year of heading to San Francisco to share in some of the latest major cybersecurity announcements, research and news. Weve pulled together the highlights, so you dont miss out on all things Talos. Tuesday, May 7 Joe Marshall will b...

What might authentication attacks look like in a phishing-resistant future?

By Thorsten Rosendahl and Tiago Pereira, with contributions from Matthew Miller. The industry has come a long way in terms of improving how we make user authentication more secure. From the most basic concept of relying on usernames and passwords for authentication to enabling multi-factor...

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...

Threat Advisory: 3CX Softphone Supply Chain Compromise

Cisco Talos is tracking and actively responding to a supply chain attack involving the 3CX Desktop Softphone application. This is a multi-stage attack that involves sideloading DLLs, seven-day sleep routines, and additional payloads dependent on a now-removed GitHub repository for Windows-based...

Ransomware and Commodity Loader Topic Summary Report: Cisco Talos Year in Review 2022

The ransomware space is dynamic, continually adapting to changes in the geopolitical environment, actions by defenders, and efforts by law enforcement, which increased in scope and intensity in 2022. This leads groups to rebrand under different names, shut down operations, and form new strategic...

See Yourself in Cyber: A Cybersecurity Awareness Month recap

As yet another October comes to an end, so does another Cybersecurity Awareness Month. Since 2004 when the President of the United States and Congress declared October Cybersecurity Awareness Month, weve taken the time to share our cybersecurity knowledge with the broader general public year afte...

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 Russias invasion of Ukraine. In this video,...

Avos ransomware group expands with new attack arsenal

By Flavio Costa, Chris Neal and Guilherme Venere. In a recent customer engagement, we observed a month-long AvosLocker campaign. The attackers utilized several different tools, including Cobalt Strike, Sliver and multiple commercial network scanners. The initial ingress point in this incident...

Threat Source newsletter (June 16, 2022) — Three top takeaways from Cisco Live

By Jon Munshaw. Welcome to this week’s edition of the Threat Source newsletter. I’m still decompressing from Cisco Live and the most human interaction I’ve had in a year and a half. But after spending a few days on the show floor and interacting with everyone, there are a... This is only the...

Talos EMEA monthly update: Business email compromise

The latest edition of the Talos EMEA Monthly Update is available now on Cisco.com and Cisco's YouTube page. You can also view the episode in its entirety above. For June, Hazel and Martin got together to discuss business email compromise. BEC has quickly become the most lucrative attack vector...

The BlackByte ransomware group is striking users all over the globe

News summary Cisco Talos has been monitoring the BlackByte Ransomware Group for several months, infecting victims all over the world, from North America to Colombia, Netherlands, China, Mexico and Vietnam.The FBI released a joint cybersecurity advisory in February 2022 warning about this group,...

Microsoft Patch Tuesday for May 2022 — Snort rules and prominent vulnerabilities

By Jon Munshaw, with contributions from Jaeson Schultz. Microsoft returned to its normal monthly patching volume in May, disclosing and fixing 74 vulnerabilities as part of the company’s latest security update. This month’s Patch Tuesday includes seven critical vulnerabilities after Microsoft...

Beers with Talos, Ep. #120: How attackers are finding ways around MFA

Beers with Talos BWT Podcast episode No. 120 is now available. Download this episode and subscribe to Beers with Talos: Apple Podcasts Google Podcasts Spotify StitcherRecorded April 6, 2022 If iTunes and Google Play aren't your thing, click here. The trend of... This is only the beginning! Please...

Threat Roundup for March 25 to April 1

Today, Talos is publishing a glimpse into the most prevalent threats we've observed between March 25 and April 1. 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...

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...

Vulnerability Spotlight: Memory corruption and use-after-free vulnerabilities in Foxit PDF Reader

Aleksandar Nikolic of Cisco Talos discovered these vulnerabilities. Blog by Jon Munshaw. Cisco Talos recently discovered a memory corruption and use-after-free vulnerability in the Foxit PDF Reader. Foxit PDF Reader is one of the most popular PDF document readers currently... This is only the...

Threat Source Newsletter (Dec. 16, 2021)

Newsletter compiled by Jon Munshaw.Good afternoon, Talos readers. I'm just going to cut to the chase since I know all anyone wants to read about is Log4J. For the latest Talos research, continually check back on our blog post here. Above is the live stream we recorded Monday morning... This is on...

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...

Beers with Talos, Ep. #111: We say goodbye to Craig and his killer robots

Beers with Talos BWT Podcast episode No. 111 is now available. Download this episode and subscribe to Beers with Talos: Apple Podcasts Google Podcasts Spotify StitcherIf iTunes and Google Play aren't your thing, click here. We apologize for holding onto this... This is only the beginning! Please...

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. 28, 2021)

Newsletter compiled by Jon Munshaw.Good afternoon, Talos readers. Most people know about chicken and waffles. But what about squirrel and waffles? They may not be the most appetizing brunch, but they are teaming up for one heck of a spam campaign. We have new research out... This is only the...

Threat Source newsletter (Sept. 30, 2021)

Newsletter compiled by Jon Munshaw.Good afternoon, Talos readers. In the latest example of attackers trying to capitalize on current headlines, we've spotted a group using the recent fervor around the Pegasus spyware to spread malware. We've detailed a campaign in which the... This is only the...

Downtime on Talos Intelligence

TalosIntelligence.com will be down for a short time on Sept. 17 around 10 a.m. ET while we perform some routine maintenance on the site. We apologize for any inconvenience this may cause. We expect the interruption will only last for about 30 minutes. This is only the beginning! Please visit the...

Talos Takes Ep. #67: What a leaked playbook tells us about the Conti ransomware group

By Jon Munshaw. The latest episode of Talos Takes is available now. Download this episode and subscribe to Talos Takes using the buttons below, or visit the Talos Takes page. There's a lot to take apart in the recently leaked Conti ransomware playbook. After a disgruntled member of the... This is...

Threat Roundup for January 29 to February 5

Today, Talos is publishing a glimpse into the most prevalent threats we've observed between Jan. 29 and Feb. 5. As with previous roundups, this post isn't meant to be an in-depth analysis. Instead, this post will summarize the threatsx we've observed by highlighting key behavioral characteristics...

Vulnerability Spotlight: Multiple vulnerabilities in PrusaSlicer

Lilith of Cisco Talos discovered these vulnerabilities. Blog by Jon Munshaw. Cisco Talos recently discovered two out-of-bounds write vulnerabilities in Prusa Research’s PrusaSlicer. Prusa Slicer is an open-source 3-D printer slicing program forked off Slic3r that can convert various 3-D model fil...

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 Sept. 17, 2020

Newsletter compiled by Jon Munshaw. Good afternoon, Talos readers. We’ve got a couple of vulnerabilities you should know about. Monday, we disclosed a bug in Google Chrome’s PDFium feature that opens the door for an adversary to execute remote code. Our researchers also discovered several...

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...

Vulnerability Spotlight: Internet Systems Consortium BIND server DoS

Emanuel Almeida of Cisco Systems discovered this vulnerability. Blog by Jon Munshaw. The Internet Systems Consortium’s BIND server contains a denial-of-service vulnerability that exists when processing TCP traffic through the libuv library. An attacker can exploit this vulnerability by flooding t...

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...

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...

Beers with Talos Ep. #86: It’s just an exploit popularity contest...

Beers with Talos BWT Podcast episode No. 85 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 June 5, 2020 Prod. Note: The team decided to hold ba...

Threat Source newsletter for June 18, 2020

Newsletter compiled by Jon Munshaw. Good afternoon, Talos readers. Now that Cisco Live is over, you can access both of Talos’ talks on-demand here if you registered for the online event. The latest Beers with Talos episode covers how to push your career in cyber security forward when you feel lik...

Vulnerability Spotlight: Two code execution vulnerabilities in Microsoft Excel

Marcin “Icewall” Noga of Cisco Talos discovered these vulnerabilities. Blog by Jon Munshaw. Cisco Talos researchers recently discovered two code execution vulnerabilities in Microsoft Excel. Microsoft released updates for these two bugs as part of their Patch Tuesday security update this week. Bo...

Threat Roundup for November 2 to November 9

Today, Talos is publishing a glimpse into the most prevalent threats we've observed between Nov. 02 and Nov. 09. 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...

Beers with Talos Ep. #38 — More fun with VPNFilter; Getting pwnd via spreadsheet

Beers with Talos BWT Podcast Ep. 38 is now available. Download this episode and subscribe to Beers with Talos: If iTunes and Google Play aren't your thing, click here. Ep. 38 show notes: Recorded Sept. 21, 2018 — The whole crew is back together! On the agenda today is VPNFilter part III, now...