Daily Brief

A viral trend of sharing AI-generated caricatures on social media poses potential risks for social engineering attacks and LLM account takeovers, according to security analyst Josh Davies. Participants in this trend may inadvertently expose sensitive personal and corporate information, increasing vulnerability to cyber threats such as credential harvesting and doxing. As of early February, over 2.6 million AI-generated images have been shared on Instagram, linking to both public and private user profiles. Attackers could exploit publicly available data from these images to identify users' email addresses and launch targeted phishing attacks. Organizations are advised to implement governance policies to monitor and limit unauthorized AI application usage and protect corporate data from potential exposure. Prompt history from LLM accounts could reveal sensitive company data if accounts are compromised, posing risks of data theft or extortion. Enhanced visibility into employee AI usage and monitoring for compromised credentials are recommended to mitigate these emerging threats.

Cybersecurity firm Koi Security identified the first malicious Microsoft Outlook add-in, named AgreeToSteal, which compromised over 4,000 user credentials through a fake login page. The attack leveraged a now-abandoned domain of a legitimate Outlook add-in, AgreeTo, exploiting the gap between project abandonment and platform detection. The malicious add-in was distributed via Microsoft's trusted store, exploiting the implicit trust users place in Microsoft Marketplace offerings. Attackers used the compromised domain to host a phishing kit, capturing credentials via a fake Microsoft sign-in page and exfiltrating data using the Telegram Bot API. The add-in's "ReadWriteItem" permissions posed a significant risk, potentially allowing attackers to read and modify users' emails, highlighting the need for enhanced monitoring. Koi Security emphasized the necessity for regular rescanning of add-in content to mitigate risks associated with dynamic URL dependencies in software marketplaces. The incident reveals broader vulnerabilities in software distribution platforms, with similar risks identified in other marketplaces like Microsoft's VS Code Marketplace. Recommendations include implementing continuous monitoring and security checks for dynamic dependencies to prevent future supply chain attacks.

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LummaStealer infections have surged, driven by CastleLoader malware campaigns using social engineering techniques like ClickFix to spread infostealing malware globally. LummaStealer, a malware-as-a-service platform, was disrupted in May 2025 by a joint operation of tech firms and law enforcement, seizing 2,300 domains. Despite the disruption, LummaStealer operations resumed by July 2025, scaling significantly by early 2026, with CastleLoader playing a central role. CastleLoader is a sophisticated script-based malware loader that employs heavy obfuscation and in-memory execution to distribute various malware families. The loader performs environment checks to evade detection and achieves persistence through strategic script placement and execution shortcuts. Bitdefender advises against downloading software from untrusted sources and warns against executing unfamiliar PowerShell commands, especially from verification pages. Detecting CastleLoader activity can be aided by monitoring for specific network behaviors, such as deliberate failed DNS lookups. Organizations are encouraged to use ad blockers to avoid malicious promoted search results and to steer clear of pirated software to mitigate infection risks.

GreyNoise suggests telcos received advance notice of a critical Telnet vulnerability, CVE-2026-24061, before its public disclosure on January 20. Telnet traffic dramatically decreased by 65% within an hour on January 14, indicating potential preemptive actions by infrastructure operators. The vulnerability, a decade-old bug in GNU InetUtils telnetd with a 9.8 CVSS score, allows for easy root access exploitation. Major telcos like BT and Cox Communications reduced Telnet sessions to zero by January 15, hinting at coordinated pre-disclosure filtering. Cloud providers, such as AWS, saw Telnet traffic increase, likely due to their extensive private peering bypassing traditional transit routes. GreyNoise theorizes Tier 1 transit providers in North America implemented port 23 filtering, affecting US ISPs but leaving European peering largely unaffected. While the correlation between traffic drop and disclosure timing is strong, GreyNoise acknowledges the lack of direct evidence for pre-advisory notifications.

Indian defense and government organizations face targeted campaigns from APT36 and SideCopy, focusing on both Windows and Linux environments with remote access trojans (RATs). The campaigns utilize malware families such as Geta RAT, Ares RAT, and DeskRAT, attributed to Pakistan-aligned threat clusters, aiming to steal sensitive data and maintain access. Attackers employ phishing emails with malicious attachments to gain initial access, leading to multi-stage processes that deploy trojans across systems. The Windows attack chain involves LNK files invoking mshta.exe to execute HTML applications, while the Linux variant uses Go binaries to deploy Ares RAT via shell scripts. The campaigns are characterized by their stealth and persistence, leveraging defense-themed lures and trusted infrastructure to evade detection. Security firms CYFIRMA and Seqrite Labs detailed the attack chains, noting the use of legitimate domains and adaptive persistence methods in response to security products. The threat actors' focus extends beyond defense, impacting policy, research, and critical infrastructure sectors, reflecting a broad strategic intent.

Over 60 software vendors, including Microsoft, Adobe, and SAP, issued security patches addressing multiple vulnerabilities across their platforms during the latest Patch Tuesday. Microsoft patched 59 vulnerabilities, with six zero-days actively exploited in the wild, affecting Windows components, potentially leading to privilege escalation and denial-of-service attacks. Adobe updated several products, including Audition and After Effects, though no active exploitation of these vulnerabilities has been reported. SAP addressed two critical vulnerabilities in its CRM and S/4HANA systems, which could allow attackers to execute arbitrary SQL statements and compromise databases. Intel and Google collaborated to identify five vulnerabilities in Intel Trust Domain Extensions 1.5, highlighting increased complexity in confidential computing environments. Organizations are advised to implement these patches promptly to mitigate potential risks and ensure business continuity. The ongoing need for robust patch management strategies is evident as vulnerabilities continue to emerge across diverse software ecosystems.

Attackers are using social engineering tactics to exploit help desks, redirecting employees' paychecks by impersonating them and manipulating internal processes. Binary Defense's ARC Labs investigated an incident where a physician's salary was redirected, revealing the attack relied on compromised credentials and social engineering. The attackers bypassed security measures by using virtual desktop infrastructure, making their actions appear as legitimate internal activity, thus avoiding detection. This incident signifies a shift from traditional email-based attacks to exploiting business processes and identity theft, posing challenges in identifying malicious activities. Organizations are advised to treat payroll platforms as high-value targets and implement additional verification steps for changes in direct deposit information. The case emphasizes the need for businesses to review and strengthen internal processes to prevent similar attacks, treating identity as a critical security perimeter. Lessons from wire fraud prevention can be applied to protect against payroll fraud, including fraud detection reviews and temporary holds on changes to financial information.

Researchers discovered a vulnerability in Notepad's Markdown feature, CVE-2026-20841, allowing remote code execution, recently patched by Microsoft in their latest security updates. The vulnerability has a CVSS score of 8.8, requiring social engineering tactics, such as phishing, to exploit, potentially affecting numerous Windows PCs with Notepad installed. Attackers can exploit this flaw by embedding malicious links in Markdown files, which, when opened in Notepad, execute files with the user's permissions. Microsoft has confirmed no known active exploitation of this vulnerability in the wild, but the risk remains due to the widespread use of Notepad. The Markdown feature was introduced in May 2025, amid debates over Notepad's transformation into a more WordPad-like application, including AI-assisted writing capabilities. Organizations are advised to ensure systems are updated with the latest patches and to educate users on recognizing phishing attempts to mitigate potential risks.

Pentera Labs identified nearly 2,000 exposed training applications in cloud environments, with 60% hosted on AWS, Azure, or GCP, posing significant security risks. These applications, intended for isolated use, were often publicly accessible and connected to privileged cloud identities, increasing potential attack vectors. Evidence of active exploitation was found, with 20% of instances showing signs of crypto-mining, webshells, and persistence mechanisms, indicating ongoing abuse. The research revealed that Fortune 500 companies, including cybersecurity leaders like Palo Alto, F5, and Cloudflare, were affected by these vulnerabilities. The study emphasizes that default credentials and public exposure, rather than advanced techniques, were sufficient for attackers to exploit these environments. Organizations often overlook training environments in security monitoring, leading to prolonged exposure and increased risk of compromise. The findings underscore the importance of including all cloud assets in security protocols, regardless of their intended use or perceived risk level.

Microsoft has released updates for 59 vulnerabilities, including six zero-days actively exploited in the wild, affecting various components of its software ecosystem. Of the 59 vulnerabilities, five are deemed Critical, with 25 involving privilege escalation, 12 remote code execution, and others spanning spoofing and information disclosure. Key zero-day vulnerabilities involve the MSHTML Framework, allowing attackers to bypass security prompts, potentially leading to unauthorized actions upon user interaction. The U.S. Cybersecurity and Infrastructure Security Agency (CISA) mandates Federal Civilian Executive Branch agencies to apply these patches by March 3, 2026. Microsoft is also enhancing security with new Secure Boot certificates and initiatives like Windows Baseline Security Mode to ensure runtime integrity safeguards. The updates aim to enhance user security transparency, requiring apps to meet higher standards for accessing sensitive resources, similar to Apple's TCC framework. Organizations are advised to prioritize these updates to mitigate risks associated with these vulnerabilities, especially those actively exploited.

The SSHStalker botnet employs IRC for command-and-control, targeting legacy Linux systems with outdated kernel vulnerabilities from 2009-2010. Flare researchers identified SSHStalker's use of a Golang scanner to automate mass compromises, focusing on servers with open SSH ports. Unlike typical botnets, SSHStalker maintains dormant access, suggesting potential for strategic use or future exploitation rather than immediate attacks. The malware toolkit includes log cleaners and rootkit artifacts, ensuring stealth by erasing traces of malicious activity to evade detection. SSHStalker leverages a repository of 16 known vulnerabilities, including CVE-2009-2692 and CVE-2010-3849, to infiltrate and control susceptible systems. Flare's analysis indicates possible Romanian origins for the threat actor, with operational patterns resembling the Outlaw hacking group. The botnet's infrastructure includes open-source offensive tools and previously known malware, showcasing mature orchestration rather than novel exploit development. Organizations relying on legacy Linux environments should prioritize patching and upgrading to mitigate risks associated with such vulnerabilities.

UK Parliament's committee questioned ministers on measures to prevent a repeat of the Afghan data breach, which exposed sensitive information of 19,000 Afghan informants. The breach resulted from a CC-not-BCC email error, highlighting the risks of legacy IT systems and human error in data handling. The government's Information Security Review recommended eliminating email-based information sharing to prevent accidental leaks, with a focus on cultural and technical changes. Ministers acknowledged the challenge of implementing new systems across departments with varying legacy IT infrastructures, emphasizing the need for investment and support. The committee pressed for transparency regarding the implementation of the review's 14 data security recommendations, with only 13.5 reportedly implemented so far. The incident underscores the critical importance of robust data security practices, especially as the UK government plans to roll out a digital ID program. Government officials committed to minimizing human error and enhancing data security measures, while acknowledging the inherent challenges in securing vast amounts of data.

North Korean threat actor UNC1069 has been targeting cryptocurrency organizations using sophisticated social engineering tactics, including AI-generated video lures and compromised communication platforms like Telegram. The group employs fake Zoom meetings and deepfake videos to deceive victims, ultimately aiming to steal sensitive data from Windows and macOS systems for financial theft. UNC1069 has shifted focus from traditional finance to the Web3 industry, targeting centralized exchanges, software developers, and venture capital firms since 2023. The attack chain involves a fake Zoom meeting link redirecting victims to phishing sites, where they are tricked into downloading malicious software under the guise of troubleshooting tools. Newly identified malware families, such as SILENCELIFT and DEEPBREATH, are used to steal credentials and browser data, enhancing UNC1069's capability to execute financial theft. The campaign's sophistication is evident in its use of multiple malware families and advanced social engineering, indicating a well-resourced and persistent threat. Organizations in the cryptocurrency sector should enhance vigilance and implement robust security measures to counteract these evolving threats.

A new Linux botnet, SSHStalker, employs the outdated IRC protocol for its command-and-control operations, prioritizing resilience and cost-effectiveness over stealth. Researchers at Flare identified that SSHStalker uses automated SSH scanning and brute forcing for initial access, masquerading as the network utility nmap. The botnet targets cloud hosting providers, particularly within Oracle Cloud infrastructure, and has scanned nearly 7,000 hosts as of January. SSHStalker employs a worm-like propagation mechanism, using compromised hosts to further scan and infect additional SSH targets. Persistence is maintained through cron jobs running every 60 seconds, ensuring the main bot process continues operating despite termination attempts. The botnet includes cryptomining capabilities and AWS key harvesting, though no DDoS attacks have been observed yet. Flare has not linked SSHStalker to a specific threat group but notes similarities with the Outlaw/Maxlas botnet ecosystem. Recommendations for mitigation include disabling SSH password authentication, removing compilers from production images, and monitoring for IRC-style connections and suspicious cron jobs.