All news with #email security tag

Hidden Text Salting: CSS Abuse in Email Threats and Evasion

🧂 Cisco Talos documents growing abuse of CSS to insert visually hidden 'salt' into emails, a technique that undermines parsing and language-detection systems. Observed across preheaders, headers, attachments and bodies between March 1, 2024 and July 31, 2025, attackers use CSS properties (font-size, opacity, display, clipping) and zero-width characters to conceal irrelevant content. Talos recommends detection plus HTML sanitization and filters—examples include Cisco Secure Email Threat Defense—to strip or ignore invisible content before downstream analysis.

Zimbra XSS Zero-Day Used to Target Brazilian Military

⚠️A stored cross-site scripting vulnerability in the Zimbra Classic Web Client (CVE-2025-27915) was exploited in targeted attacks and has since been patched. The flaw allowed embedded JavaScript in ICS calendar entries to execute via an ontoggle event, enabling attackers to create mail filters, redirect messages, and exfiltrate mailbox data. Zimbra released fixes on January 27, 2025; administrators should apply updates and audit mailbox filters and logs for indicators of compromise.

New MatrixPDF Phishing Technique Targets Gmail Users

📄 Researchers at Varonis have identified a sophisticated phishing toolkit called MatrixPDF that embeds prompts, JavaScript, and external redirects inside seemingly legitimate PDF files to target Gmail users. Attackers exploit Gmail's preview and desktop PDF readers: a blurred preview displays a prompt to 'open secure document' that directs victims to external payloads, while embedded scripts can fetch malware if a user grants permission. Because the malicious content is only retrieved after user interaction, Gmail's automated scanners and attachment sandboxes can be bypassed. Security experts recommend stronger webmail controls, robust attachment sandboxing, endpoint detection, and frequent, realistic user awareness training.

State-Sponsored Attacks Exploit Libraesva ESG Vulnerability

⚠️ Libraesva has released an urgent update to address a command injection vulnerability in its ESG email security product that is being exploited by state‑sponsored actors. Tracked as CVE-2025-59689 with a CVSS score of 6.1, the flaw is triggered by a malicious compressed attachment and can execute arbitrary commands as a non‑privileged user. Users should upgrade affected versions (4.5–5.5.x before 5.5.7) to the patched releases immediately.