“Comment Stuffing” in HTML Phishing Attachments Used to Bypass AI Detection
What Happened – Researchers observed a new evasion technique where attackers embed large blocks of HTML comments (“comment stuffing”) inside phishing attachments. The extra comment data confuses AI‑based email‑security models, allowing the malicious payload to slip past basic filters.
Why It Matters for Compliance & Audit Readiness
- The technique targets the very controls SOC 2 CC6.1 (Security) expects: robust email‑filtering and documented phishing‑resilience testing.
- Continuous‑compliance programs must prove that awareness training and detection controls are regularly validated against emerging tactics.
- Verisq’s Security Awareness Training capability supplies audit‑ready evidence that staff and detection rules are kept current.
Who Is Affected – All sectors that rely on email for business communications, especially technology‑SaaS firms, financial services, and professional services.
Recommended Actions
- Map the phishing‑evasion scenario to SOC 2 CC6.1 and CC6.2 controls; capture training records and filter‑rule updates as evidence.
- Augment security‑awareness curricula with a module on “HTML comment stuffing” and run simulated phishing campaigns that include the technique.
- Test your AI‑based email filters using crafted samples that contain comment stuffing; document results for audit review.
Technical Notes – The evasion does not exploit a CVE; it leverages HTML comment syntax to inflate payload size and dilute malicious signatures, reducing the confidence score of AI classifiers. No new malware families were disclosed.