Shattering the Dream – When a Job Offer Becomes a Zero-Day Attack

Key Points

• Check Point Research is tracking a long‑running campaign called Operation Dream Job, targeting organizations worldwide, with a particular focus on the defense sector. The campaign is affiliated to DPRK-linked Lazarus group and its latest wave focuses on the defense sector in Europe and India.
• In the latest variant of the Operation Dream Job campaign, the threat actor distributed SecurityPDF, a modified PDF viewer designed to open attacker-crafted PDF documents and execute a new backdoor which we named Troy.
• During the intrusion, the threat actor exploited CVE-2026-68820, a zero-day vulnerability in the Microsoft AFD.sys driver, to deploy a new version of FudModule, Lazarus’ kernel-mode rootkit. Following Check Point Research responsible disclosure, Microsoft released a patch as part of their August Patch Tuesday updates.
• Lazarus also used CVE-2025-49113 to exploit vulnerable Roundcube webmail servers. The compromised servers were infected with RelayShell, a PHP webshell that repurposes compromised web servers as relay nodes within the attacker’s command-and-control infrastructure.
• At least in one case, a compromised organization in Western Europe was leveraged to conduct a spear-phishing campaign, allowing the attackers to abuse the organization’s reputation and trust to target additional victims.

Introduction

Since early 2026, Check Point Research has tracked a wave of the Operation Dream Job campaign. This wave primarily targeted the defense sector worldwide, with a particular emphasis on companies operating in the aerospace and aviation industries.

We observed the threat actor distributing modified PDF viewers designed to execute malicious payloads embedded within specially crafted PDF files, opened by the user. In this campaign, the threat actor expanded its delivery method by leveraging impersonation websites and search engine optimization (SEO) techniques to distribute the trojanized applications, increasing its credibility and helping it evade some phishing-based detections.

During the operation, the threat actor deployed a new version of the FudModule rootkit, exploiting a zero-day local privilege escalation (LPE) vulnerability in the Windows AFD.sys driver, to obtain SYSTEM privileges and disable EDR visibility. Following responsible disclosure, Microsoft assigned the vulnerability CVE-2026-68820 and released a patch on August 11, 2026, as part of their August Patch Tuesday updates.

The attackers’ command-and-control infrastructure consists of compromised Roundcube and WordPress servers hosting RelayShell, a new PHP webshell that repurposes compromised web servers as relay nodes.

In this blog, we analyze the latest Operation Dream Job campaign, walking through the complete attack chain and providing a technical analysis of the malware and the novel techniques employed throughout the operation, offering new insights into the group’s evolving modus operandi.

Infection Chain

The Operation Dream Job campaign begins with targeted spear-phishing lures centered on attractive job opportunities at well-known companies in the defense, aerospace, and aviation industries.

The exact method used to approach victims in the current campaign remains unclear. However, based on previously documented Dream Job campaigns, we assess that the threat actor likely approached targets through professional networking platforms such as LinkedIn, or directly through messaging applications. Posing as recruiters, the attackers present enticing job opportunities and ultimately direct victims to download malicious files.

During our analysis, we identified two distinct infection chains used to compromise targets. While the second chain appears to represent a more recent evolution of the campaign, both infection methods remain active in parallel.

Infection Chain 1: DLL Sideloading chain

In this infection chain, the victim is convinced to download an encrypted zip archive containing three files:

• A legitimate, digitally signed PDF viewer executable.
• A malicious DLL that is loaded through DLL sideloading.
• An encrypted payload with a PDF extension.

When the victim launches the executable, the malicious DLL libmupdf.dll is loaded via DLL sideloading. The DLL extracts a decoy PDF document from the encrypted payload and displays it to the user, while simultaneously extracting, decrypting, and executing an embedded payload directly in memory.

The executed payload is MISTPEN, a lightweight in-memory downloader that uses Microsoft Graph API to access OneDrive in order to retrieve additional modules and run them in memory.

• Reconnaissance: During the initial stages of the infection, the threat actor deploys several reconnaissance modules that collect system and process information, allowing the attacker to verify that the system is a suitable target before proceeding with the next stage of the attack.
• Persistence: Once the target has been validated, MISTPEN receives an additional persistence module that installs the malware on disk and ensures that MISTPEN is automatically executed after system reboot.
• Privilege Escalation: After persistence is established, MISTPEN loads an in-memory local privilege escalation (LPE) module designed to exploit the zero day vulnerability CVE-2026-68820 in the Microsoft AFD.sys driver. Successful exploitation allows the malware to execute FudModule, Lazarus’ kernel-mode rootkit, with SYSTEM privileges.
• Backdoor Deployment: The final backdoor delivered by MISTPEN is the ForestTiger backdoor, a well-documented malware family widely attributed to the Lazarus threat group. Once deployed, it provides the attackers with long-term remote access to the compromised host.

Infection Chain 2: Trojanized PDF viewer

In July 2026, we observed a new campaign sharing many characteristics with previously documented Operation Dream Job, particularly the campaign described by ESET in 2025.

In this infection chain, victims receive fraudulent job offers impersonating Enveil, a Privacy Enhancing Technology company, and are instructed to download an encrypted ZIP archive containing two files:

• SecurityPDF – a trojanized PDF viewer that has been modified to extract and execute an encrypted payload from specially crafted PDF documents.
• A malicious PDF file – an encrypted payload disguised as a PDF document that is decrypted and executed when opened with the modified viewer.

SecurityPDF is a trojanized version of a legitimate open-source PDF viewer built on the MuPDF framework. The threat actor modified two code paths responsible for openi

Key Takeaways

• Operation Dream Job campaign targets defense sectors in Europe and India.
• Lazarus group uses zero-day CVE-2026-68820 in AFD.sys driver for attacks.
• Compromised Roundcube servers are repurposed as relay nodes via RelayShell webshell.