Self-contained HTML phishing attachment using Telegram to exfiltrate stolen credentials, Author: Jan Kopriva

Anyone who has had to deal with HTML emails on a technical level has probably reached the point where they wanted to quit their job or just set fire to all the mail clients due to their inconsistent implementations. But HTML emails are not just a source of frustration, they can also be a serious security risk.

Read the new Microsoft Threat Intelligence tax season report to learn about the techniques that threat actors use to mislead taxpayers.

In the last couple of months, Check Point Research (CPR) has been tracking the activity of a Chinese threat actor targeting Foreign Affairs ministries and embassies in Europe. Combined with other Chinese activity previously reported by Check Point Research, this represents a larger trend within the Chinese ecosystem, pointing to a shift to targeting European entities, with a focus on their foreign policy.

The activity described in this report, utilizes HTML Smuggling to target governmental entities in Eastern Europe. This specific campaign has been active since at least December 2022, and is likely a direct continuation of a previously reported campaign attributed to RedDelta (and also to Mustang Panda, to some extent).

Last October, Trustwave SpiderLabs blogged about the use and prevalence of HTML email attachments to deliver malware and phishing for credentials.