In a concerning development for cybersecurity professionals worldwide, Ukrainian organizations have become the latest targets of a sophisticated zero-day cyberattack. Security researchers have identified CVE-2025-0411, a critical vulnerability in the widely used 7-Zip archiver, actively exploited in a campaign leveraging homoglyph attacks. This vulnerability allows attackers to bypass Windows’ Mark-of-the-Web (MoTW) protections, enabling the execution of malicious files without triggering security alerts.
The campaign, attributed to Russian cybercrime groups, underscores the increasing weaponization of zero-day exploits in cyberwarfare.
The attack has primarily targeted Ukrainian government and civilian organizations, deploying SmokeLoader malware through spear-phishing campaigns. The exploitation of homoglyph attacks to trick users into executing malicious payloads adds a new layer of complexity, making it imperative for organizations to adopt stronger cybersecurity measures.
Understanding CVE-2025-0411
CVE-2025-0411 is a zero-day vulnerability in 7-Zip that allows threat actors to circumvent Microsoft Windows’ MoTW protections. When files are downloaded from an untrusted source, Windows assigns them a Zone.Identifier tag (ZoneId=3) to indicate that additional security checks are required before execution. However, the vulnerability exploits a flaw in 7-Zip’s handling of nested archives, where the inner files remain untagged, effectively bypassing MoTW protections.
Key Technical Details:
- Vulnerability Name: CVE-2025-0411
- Affected Software: 7-Zip (versions prior to 24.09)
- Exploit Method: Double archiving (nested archives) to bypass MoTW
- Impact: Enables execution of malicious scripts without triggering security prompts
- Patch Released: November 30, 2024 (7-Zip version 24.09)
Attack Methodology
Phase 1: Spear-Phishing Campaign
The attackers leveraged compromised Ukrainian government email accounts to send phishing emails containing malicious 7-Zip attachments. These emails were crafted to appear legitimate, often impersonating official correspondence related to financial transactions or legal documents.
Phase 2: Homoglyph-Based Deception
A homoglyph attack involves the use of visually similar characters from different character sets to deceive users. In this case, attackers modified file extensions by replacing Latin characters with Cyrillic counterparts (e.g., replacing ‘c’ with ‘с’ from the Cyrillic alphabet). This allowed malicious executables to masquerade as benign document files (.doc, .pdf).
Phase 3: Exploiting CVE-2025-0411
Once the victim opened the seemingly innocuous file, 7-Zip extracted the inner archive, which lacked MoTW protections. This enabled the execution of malicious scripts without Windows issuing a security warning. The SmokeLoader malware was then deployed, granting attackers full control over the compromised system.
Impacted Organizations
Based on intelligence reports, the following Ukrainian organizations have been affected or targeted:
- State Executive Service of Ukraine (SES) – Ministry of Justice
- Zaporizhzhia Automobile Building Plant (PrJSC ZAZ)
- Kyiv Public Transportation Service (Kyivpastrans)
- SEA Company – Electrical Equipment Manufacturer
- Kyivvodokanal – Kyiv Water Supply Company
- Various municipal councils and government entities
These attacks highlight the vulnerability of both governmental and private sector organizations in conflict zones.
10 Measures to Prevent Such Attacks
- Update 7-Zip Immediately – Ensure all systems are running version 24.09 or later to mitigate CVE-2025-0411.
- Enhance Email Security – Implement advanced email filtering to detect phishing attempts and block suspicious attachments.
- Train Employees on Phishing Tactics – Conduct regular cybersecurity awareness training, focusing on spear-phishing and homoglyph attacks.
- Enable Microsoft Defender SmartScreen – Ensure SmartScreen is activated to detect and block potentially malicious files.
- Restrict Macro Execution in Office Files – Configure Microsoft Office to block macros in documents downloaded from the internet.
- Implement Application Whitelisting – Only allow approved applications to run on enterprise systems.
- Monitor Network Traffic for Anomalies – Use network intrusion detection systems (NIDS) to identify suspicious activity.
- Deploy Endpoint Detection and Response (EDR) Solutions – Implement EDR tools to detect and mitigate advanced persistent threats.
- Use Multi-Factor Authentication (MFA) – Require MFA for all user logins to reduce the risk of account compromise.
- Conduct Regular Security Audits – Perform vulnerability assessments to identify and remediate security gaps.
Conclusion
The exploitation of CVE-2025-0411 in targeted cyberattacks against Ukrainian organizations exemplifies the growing sophistication of nation-state cyber warfare. By leveraging zero-day vulnerabilities and homoglyph attacks, threat actors are refining their tactics to bypass security mechanisms and gain unauthorized access to critical systems.
The incident underscores the importance of timely patching, robust email security, and continuous user education. As cyber threats evolve, organizations must remain vigilant, adopt a proactive security stance, and leverage advanced threat intelligence to safeguard their digital assets.
