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Cloudflare on Wednesday said it detected and mitigated the largest ever distributed denial-of-service (DDoS) attack that measured at 29.7 terabits per second (Tbps). The activity, the web infrastructure and security company said, originated from a DDoS botnet-for-hire known as AISURU , which has been linked to a number of hyper-volumetric DDoS attacks over the past year. The attack lasted for 69 seconds. It did not disclose the target of the attack. The botnet has prominently targeted telecommunication providers, gaming companies, hosting providers, and financial services. Also tackled by Cloudflare was a 14.1 Bpps DDoS attack from the same botnet. AISURU is believed to be powered by a massive network comprising an estimated 1-4 million infected hosts worldwide. "The 29.7 Tbps was a UDP carpet-bombing attack bombarding an average of 15,000 destination ports per second," Omer Yoachimik and Jorge Pacheco said . "The distributed attack randomized various packet attrib...

Cybersecurity researchers are calling attention to a nefarious campaign targeting WordPress sites to make malicious JavaScript injections that are designed to redirect users to sketchy sites. "Site visitors get injected content that was drive-by malware like fake Cloudflare verification," Sucuri researcher Puja Srivastava said in an analysis published last week. The website security company said it began an investigation after one of its customer's WordPress sites served suspicious third-party JavaScript to site visitors, ultimately finding that the attackers introduced malicious modifications to a theme-related file ("functions.php"). The code inserted into "functions.php" incorporates references to Google Ads, likely in an attempt to evade detection. But, in reality, it functions as a remote loader by sending an HTTP POST request to the domain "brazilc[.]com," which, in turn, responds with a dynamic payload that includes two component...

Cybersecurity researchers have disclosed details of a new botnet that customers can rent access to conduct distributed denial-of-service (DDoS) attacks against targets of interest. The ShadowV2 botnet, according to Darktrace, predominantly targets misconfigured Docker containers on Amazon Web Services (AWS) cloud servers to deploy a Go-based malware that turns infected systems into attack nodes and co-opt them into a larger DDoS botnet. The cybersecurity company said it detected the malware targeting its honeypots on June 24, 2025. "At the center of this campaign is a Python-based command-and-control (C2) framework hosted on GitHub Codespaces," security researcher Nathaniel Bill said in a report shared with The Hacker News. "What sets this campaign apart is the sophistication of its attack toolkit. The threat actors employ advanced methods such as HTTP/2 Rapid Reset , a Cloudflare under attack mode ( UAM ) bypass, and large-scale HTTP floods, demonstrating a capabi...

Microsoft's Digital Crimes Unit said it teamed up with Cloudflare to coordinate the seizure of 338 domains used by RaccoonO365 , a financially motivated threat group that was behind a phishing-as-a-service (Phaas) toolkit used to steal more than 5,000 Microsoft 365 credentials from 94 countries since July 2024. "Using a court order granted by the Southern District of New York, the DCU seized 338 websites associated with the popular service, disrupting the operation's technical infrastructure and cutting off criminals' access to victims," Steven Masada, assistant general counsel at DCU, said . "This case shows that cybercriminals don't need to be sophisticated to cause widespread harm – simple tools like RaccoonO365 make cybercrime accessible to virtually anyone, putting millions of users at risk." The initial phase of the Cloudflare takedown commenced on September 2, 2025, with additional actions occurring on September 3 and September 4. This in...

Cloudflare on Tuesday said it automatically mitigated a record-setting volumetric distributed denial-of-service (DDoS) attack that peaked at 11.5 terabits per second (Tbps). "Over the past few weeks, we've autonomously blocked hundreds of hyper-volumetric DDoS attacks, with the largest reaching peaks of 5.1 Bpps and 11.5 Tbps," the web infrastructure and security company said in a post on X. "The 11.5 Tbps attack was a UDP flood that mainly came from Google Cloud." The entire attack lasted only about 35 seconds, with the company stating its "defenses have been working overtime." Volumetric DDoS attacks are designed to overwhelm a target with a tsunami of traffic, causing the server to slow down or even fail. These attacks typically result in network congestion, packet loss, and service disruptions. Such attacks are often conducted by sending the requests from botnets that are already under the control of the threat actors after having infected t...

Cybersecurity researchers have called attention to a cyber attack in which unknown threat actors deployed an open-source endpoint monitoring and digital forensic tool called Velociraptor , illustrating ongoing abuse of legitimate software for malicious purposes. "In this incident, the threat actor used the tool to download and execute Visual Studio Code with the likely intention of creating a tunnel to an attacker-controlled command-and-control (C2) server," the Sophos Counter Threat Unit Research Team said in a report published this week.  While threat actors are known to adopt living-off-the-land (LotL) techniques or take advantage of legitimate remote monitoring and management (RMM) tools in their attacks, the use of Velociraptor signals a tactical evolution, where incident response programs are being used to obtain a foothold and minimize the need for having to deploy their own malware.  Further analysis of the incident has revealed that the attackers used the Wind...

Cybersecurity researchers have disclosed details of a new phishing campaign that conceals malicious payloads by abusing link wrapping services from Proofpoint and Intermedia to bypass defenses. "Link wrapping is designed by vendors like Proofpoint to protect users by routing all clicked URLs through a scanning service, allowing them to block known malicious destinations at the moment of click," the Cloudflare Email Security team said . "While this is effective against known threats, attacks can still succeed if the wrapped link hasn't been flagged by the scanner at click time." The activity, observed over the last two months, once again illustrates how threat actors find different ways to leverage legitimate features and trusted tools to their advantage and perform malicious actions, in this case, redirecting victims to Microsoft 365 phishing pages. It's noteworthy that the abuse of link wrapping involves the attackers gaining unauthorized access to em...

Cybersecurity researchers have shed light on a new versatile malware loader called CastleLoader that has been put to use in campaigns distributing various information stealers and remote access trojans (RATs). The activity employs Cloudflare-themed ClickFix phishing attacks and fake GitHub repositories opened under the names of legitimate applications, Swiss cybersecurity company PRODAFT said in a report shared with The Hacker News. The malware loader, first observed in the wild earlier this year, has been used to distribute DeerStealer , RedLine , StealC , NetSupport RAT , SectopRAT , and even other loaders like Hijack Loader . "It employs dead code injection and packing techniques to hinder analysis," the company said. "After unpacking itself at runtime, it connects to a C2 (command-and-control) server, downloads target modules, and executes them." CastleLoader's modular structure allows it to act as both a delivery mechanism and a staging utility, enabling...

Cloudflare on Tuesday said it mitigated 7.3 million distributed denial-of-service (DDoS) attacks in the second quarter of 2025, a significant drop from 20.5 million DDoS attacks it fended off the previous quarter. "Overall, in Q2 2025, hyper-volumetric DDoS attacks skyrocketed," Omer Yoachimik and Jorge Pacheco said . "Cloudflare blocked over 6,500 hyper-volumetric DDoS attacks, an average of 71 per day." In Q1 2025, the company said an 18-day sustained campaign against its own and other critical infrastructure protected by Cloudflare was responsible for 13.5 million of the attacks observed during the time period. Cumulatively, Cloudflare has blocked nearly 28 million DDoS attacks, surpassing the number of attacks it mitigated in all of 2024. The notable of the attacks in Q2 2025 is a staggering DDoS attack that peaked at 7.3 terabits per second (Tbps) and 4.8 billion packets per second (Bpps) within a span of 45 seconds. Big traffic spikes like these make he...

Threat actors behind the Interlock ransomware group have unleashed a new PHP variant of its bespoke remote access trojan (RAT) as part of a widespread campaign using a variant of ClickFix called FileFix. "Since May 2025, activity related to the Interlock RAT has been observed in connection with the LandUpdate808 (aka KongTuke) web-inject threat clusters," The DFIR Report said in a technical analysis published today in collaboration with Proofpoint. "The campaign begins with compromised websites injected with a single-line script hidden in the page's HTML, often unbeknownst to site owners or visitors." The JavaScript code acts as a traffic distribution system (TDS), using IP filtering techniques to redirect users to fake CAPTCHA verification pages that leverage ClickFix to entice them into running a PowerShell script that leads to the deployment of NodeSnake (aka Interlock RAT or Supper ). The use of NodeSnake by Interlock was previously documented by Qu...

Cloudflare on Thursday said it autonomously blocked the largest distributed denial-of-service (DDoS) attack ever recorded, which hit a peak of 7.3 terabits per second (Tbps). The attack, which was detected in mid-May 2025, targeted an unnamed hosting provider. "Hosting providers and critical Internet infrastructure have increasingly become targets of DDoS attacks," Cloudflare's Omer Yoachimik said . "The 7.3 Tbps attack delivered 37.4 terabytes in 45 seconds." Earlier this January, the web infrastructure and security company said it had mitigated a 5.6 Tbps DDoS attack aimed at an unnamed internet service provider (ISP) from Eastern Asia. The attack originated from a Mirai-variant botnet in October 2024. Then in April 2025, Cloudflare revealed it defended against a massive 6.5 Tbps flood that likely emanated from Eleven11bot, a botnet comprising roughly 30,000 webcams and video recorders. The hyper-volumetric attack lasted about 49 seconds. The 7.3 Tbps...

A new campaign is making use of Cloudflare Tunnel subdomains to host malicious payloads and deliver them via malicious attachments embedded in phishing emails. The ongoing campaign has been codenamed SERPENTINE#CLOUD by Securonix. It leverages "the Cloudflare Tunnel infrastructure and Python-based loaders to deliver memory-injected payloads through a chain of shortcut files and obfuscated scripts," security researcher Tim Peck said in a report shared with The Hacker News. The attack starts with sending payment- or invoice-themed phishing emails bearing a link to a zipped document that contains a Windows shortcut (LNK) file. These shortcuts are disguised as documents to trick victims into opening them, effectively activating the infection sequence. The elaborate multi-step process culminates in the execution of a Python-based shellcode loader that executes payloads packed with the open-source Donut loader entirely in memory. Securonix said the campaign has targeted the...

Cybersecurity researchers have exposed a previously unknown threat actor known as Water Curse that relies on weaponized GitHub repositories to deliver multi-stage malware. "The malware enables data exfiltration (including credentials, browser data, and session tokens), remote access, and long-term persistence on infected systems," Trend Micro researchers Jovit Samaniego, Aira Marcelo, Mohamed Fahmy, and Gabriel Nicoleta said in an analysis published this week. The "broad and sustained" campaign, first spotted last month, set up repositories offering seemingly innocuous penetration testing utilities, such as SMTP email bomber and Sakura-RAT, but harbored within their Visual Studio project configuration files malicious payloads that are designed to siphon sensitive data. Water Curse's arsenal incorporates a wide range of tools and programming languages, underscoring their cross-functional development capabilities to target the supply chain with "develope...

Microsoft is calling attention to an ongoing malvertising campaign that makes use of Node.js to deliver malicious payloads capable of information theft and data exfiltration. The activity, first detected in October 2024, uses lures related to cryptocurrency trading to trick users into installing a rogue installer from fraudulent websites that masquerade as legitimate software like Binance or TradingView. The downloaded installer comes embedded with a dynamic-link library ("CustomActions.dll") that's responsible for harvesting basic system information using Windows Management Instrumentation (WMI) and setting up persistence on the host via a scheduled task. In an attempt to keep up the ruse, the DLL launches a browser window via " msedge_proxy.exe " that displays the legitimate cryptocurrency trading website. It's worth noting that "msedge_proxy.exe" can be used to display any website as a web application. The scheduled task, in the meanwhile...