New “MalDoc in PDF” Technique Allows Malware to Bypass Antivirus

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Cybersecurity Alert: Innovative Attack Method Discovered

MalDoc in PDF: A Stealthy Malware Delivery Method

Cybersecurity experts have revealed a clever tactic called “MalDoc in PDF,” which enables attackers to embed malicious Microsoft Word files within innocent-looking PDF documents. This evasion technique, discovered in a real-world attack in July 2023, poses a significant threat to antivirus defenses.

Polyglot Files and Sneaky Macros

MalDoc in PDF relies on polyglot files that masquerade as both PDFs and Word (DOC) files. Attackers insert a Word-created MHT (MIME-type HTML) file with an attached macro into the PDF, creating a seemingly legitimate PDF that can also open in Microsoft Word. Once opened, the embedded macro can download and install malware, thou

gh the specific malware remains unknown.

User Interaction Required

To execute this malware, user interaction is essential. When users download or receive such files, they encounter a “Mark of the Web” (MotW) and must click “Enable Editing” to exit Protected View. At this point, they are alerted that macros are disabled, providing an additional layer of security.

Ongoing Threat and QR Code Phishing

MalDoc in PDF attacks only emerged a little over a month ago, but evidence suggests that attackers experimented with this technique as early as May. The cybersecurity landscape is e

ver-evolving, demanding continuous vigilance.

Rise in QR Code Phishing

In addition to MalDoc in PDF, phishing campaigns are on the rise, with attackers using QR codes to distribute malicious URLs—a trend known as “qishing.” These campaigns often impersonate multi-factor authentication (MFA) notifications, tricking users into scanning

QR codes that lead to phishing pages.

Social Engineering Sophistication

Threat actors are refining their social engineering tactics. For instance, a recent attack involved a fake delivery driver who coerced an employee into reading a code received via email, ultimately facilitating data theft.

DNS Security Concerns

Amidst these evolving threats, concerns have emerged regarding DNS name collisions, which could

potentially leak sensitive data. Certain top-level domains (TLDs) behave unpredictably, resolving unregistered or expired domain names to IP addresses and collecting emails for nonexistent addresses.

Summary

As cybersecurity threats advance, staying informed and adopting robust security practices is crucial for protecting against emerging techniques like MalDoc in PDF, as well as the ever-present risk of social engineering attacks. Remain vigilant to mitigate these evolving threats.

Courtesy: The Hacker News

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