WinRAR (RARLAB)

WinRAR (RARLAB)

A critical zero-day vulnerability (CVE-2025-8088) in **WinRAR’s Windows version (pre-7.13)** enabled path traversal attacks, allowing threat actors to deploy malware via malicious RAR archives. Exploited by **RomCom (Storm-0978)** and **Paper Werewolf (GOFFEE)**, the flaw facilitated phishing campaigns targeting financial, manufacturing, defense, and logistics sectors in **Europe, Canada, and Russia**. Attackers disguised malicious archives as job resumes or official communications, deploying backdoors (SnipBot, RustyClaw, Mythic) for persistence and data exfiltration. The exploit leveraged **alternate data streams (ADS)** to hide payloads in Windows Startup folders, achieving **remote code execution** upon user login. While no mass exploitation was reported by August 2025, the vulnerability’s **public disclosure (CVSS 8.8)** and dark web sale ($80,000) heightened risks of copycat attacks. Organizations faced potential **data breaches, system compromises, and operational disruptions**, though no confirmed large-scale data leaks or ransomware incidents were tied to this flaw. Patching (WinRAR 7.13) mitigated the risk, but delayed updates left users exposed to **targeted cyber espionage and financial theft**.

Source: https://cybersecuritynews.com/winrar-0-day-exploited/

TPRM report: https://www.rankiteo.com/company/win.rar-gmbh

"id": "win748081525",
"linkid": "win.rar-gmbh",
"type": "Vulnerability",
"date": "8/2025",
"severity": "85",
"impact": "4",
"explanation": "Attack with significant impact with customers data leaks"
{'affected_entities': [{'industry': ['Finance',
                                     'Manufacturing',
                                     'Defense',
                                     'Logistics'],
                        'location': ['Europe', 'Canada'],
                        'name': 'Unspecified organizations in Europe/Canada',
                        'type': ['Financial institutions',
                                 'Manufacturing firms',
                                 'Defense contractors',
                                 'Logistics companies']},
                       {'location': 'Russia',
                        'name': 'Unspecified Russian organizations'}],
 'attack_vector': ['Malicious RAR archives',
                   'Phishing emails (job applications, official '
                   'communications)',
                   'Alternate Data Streams (ADS)',
                   'Specially crafted file paths'],
 'customer_advisories': ['Avoid opening RAR files from untrusted sources.',
                         'Verify WinRAR version and update manually if '
                         'necessary.',
                         'Report suspicious job application emails with '
                         'attachments.'],
 'data_breach': {'data_exfiltration': ['Likely (via SnipBot/RustyClaw '
                                       'backdoors)'],
                 'file_types_exposed': ['DLL files',
                                        'Malicious payloads hidden in RAR '
                                        'archives'],
                 'sensitivity_of_data': 'High (defense, financial, and '
                                        'logistics sectors targeted)',
                 'type_of_data_compromised': ['Potential corporate data',
                                              'System credentials (via '
                                              'backdoors)']},
 'date_detected': '2025-07-18',
 'date_publicly_disclosed': '2025-07-18',
 'date_resolved': '2025-07-30',
 'description': 'A zero-day vulnerability (CVE-2025-8088) in WinRAR for '
                'Windows allows attackers to execute arbitrary code via '
                'specially crafted archives. The path traversal flaw stems '
                'from improper handling of file paths during extraction, '
                'enabling malicious archives to place files in unauthorized '
                'locations (e.g., Windows Startup folders). Attackers leverage '
                'alternate data streams (ADS) to hide payloads in benign RAR '
                'files, deploying silently upon extraction. Exploitation has '
                'been linked to RomCom (Storm-0978) and Paper Werewolf '
                '(GOFFEE) threat groups, targeting financial, manufacturing, '
                'defense, logistics, and Russian organizations via phishing '
                'emails disguised as job applications or official '
                'communications. The exploit was patched in WinRAR 7.13, '
                'released on July 30, 2025.',
 'impact': {'brand_reputation_impact': ['High (due to zero-day association '
                                        'with WinRAR)',
                                        'Erosion of trust in file-sharing '
                                        'tools'],
            'data_compromised': ['Potential corporate/defense data (via '
                                 'backdoors)',
                                 'User system integrity'],
            'operational_impact': ['Risk of remote code execution on next '
                                   'login',
                                   'Potential for lateral movement within '
                                   'networks'],
            'systems_affected': ['Windows systems running WinRAR < 7.13',
                                 'Startup folders',
                                 '%TEMP% directories']},
 'initial_access_broker': {'backdoors_established': ['SnipBot',
                                                     'RustyClaw',
                                                     'Mythic agents'],
                           'data_sold_on_dark_web': ['Exploit code sold for '
                                                     '$80,000 in late June '
                                                     '2025'],
                           'entry_point': ['Phishing emails with malicious RAR '
                                           'attachments',
                                           'Exploit purchased on dark web '
                                           'forum ($80,000 in late June 2025)'],
                           'high_value_targets': ['Financial, manufacturing, '
                                                  'defense, logistics sectors '
                                                  '(RomCom)',
                                                  'Russian organizations '
                                                  '(Paper Werewolf)'],
                           'reconnaissance_period': ['RomCom: July 18–21, 2025',
                                                     'Paper Werewolf: Timing '
                                                     'unspecified (post-June '
                                                     '2025)']},
 'investigation_status': 'Ongoing (as of 2025-08-15; no widespread attacks '
                         'beyond targeted phishing reported)',
 'lessons_learned': ['Delayed patching exacerbates risks in widely used '
                     'software.',
                     'Compressed files (e.g., RAR) remain high-risk vectors '
                     'for phishing.',
                     'Alternate Data Streams (ADS) can bypass traditional '
                     'security controls.',
                     'Threat actors rapidly adopt zero-days sold on dark web '
                     'forums.',
                     'Manual update checks are critical for software lacking '
                     'auto-update features.'],
 'motivation': ['Espionage',
                'Data exfiltration',
                'Persistence',
                'Financial gain (exploit sold for $80,000)'],
 'post_incident_analysis': {'corrective_actions': ['Patch path traversal '
                                                   'vulnerability in WinRAR '
                                                   '7.13.',
                                                   'Enhance email filtering '
                                                   'for RAR attachments.',
                                                   'Improve user education on '
                                                   'phishing and manual '
                                                   'updates.',
                                                   'Monitor for copycat '
                                                   'campaigns post-public '
                                                   'disclosure.'],
                            'root_causes': ['Improper file path handling in '
                                            'WinRAR’s extraction logic.',
                                            'Lack of auto-update mechanism for '
                                            'older WinRAR versions.',
                                            'Effectiveness of phishing as an '
                                            'initial access vector.',
                                            'Rapid weaponization of zero-days '
                                            'post-dark web sale.']},
 'recommendations': ['Immediately update WinRAR to version 7.13 or later.',
                     'Block RAR attachments in email gateways where possible.',
                     'Scan systems for indicators of compromise (e.g., '
                     'unexpected files in Startup/%TEMP%).',
                     'Educate employees on phishing risks, especially job '
                     'application-themed emails.',
                     'Monitor dark web forums for exploit sales to anticipate '
                     'attacks.',
                     'Implement network segmentation to limit lateral '
                     'movement.',
                     'Use behavioral analysis tools to detect anomalous file '
                     'extraction behavior.'],
 'references': [{'date_accessed': '2025-07-18', 'source': 'ESET Research'},
                {'date_accessed': '2025-07-30',
                 'source': 'WinRAR Changelog (Version 7.13)'},
                {'source': 'CVSS Score (8.8)'}],
 'response': {'communication_strategy': ['Public advisory via ESET and WinRAR',
                                         'Demonstration video (with caution '
                                         'against unverified sources)',
                                         'Urgent update notifications'],
              'containment_measures': ['Patch release (WinRAR 7.13 on '
                                       '2025-07-30)',
                                       'Scanning for indicators of compromise '
                                       '(e.g., unexpected files in %TEMP% or '
                                       'Startup directories)',
                                       'Enhanced email filtering to block RAR '
                                       'attachments'],
              'enhanced_monitoring': ['Monitoring for exploit attempts '
                                      'post-disclosure'],
              'incident_response_plan_activated': True,
              'remediation_measures': ['Manual update checks (via Help > About '
                                       'WinRAR)',
                                       'Download updates from official sources '
                                       'only',
                                       'User education on phishing risks'],
              'third_party_assistance': ['ESET researchers (discovery and '
                                         'analysis)']},
 'stakeholder_advisories': ['Urgent patching advisory for WinRAR users.',
                            'Warning about phishing campaigns leveraging RAR '
                            'attachments.',
                            'Guidance for detecting exploitation attempts '
                            '(e.g., unexpected files in Startup folders).'],
 'threat_actor': [{'alignment': 'Russia-aligned',
                   'malware_deployed': ['SnipBot',
                                        'RustyClaw',
                                        'Mythic agents'],
                   'name': 'RomCom (Storm-0978)',
                   'tactics': 'Phishing (malicious RAR attachments disguised '
                              'as resumes)',
                   'targets': ['Financial sector',
                               'Manufacturing',
                               'Defense',
                               'Logistics (Europe, Canada)']},
                  {'name': 'Paper Werewolf (GOFFEE)',
                   'tactics': 'Phishing (mimicking official communications '
                              'from a research institute)',
                   'targets': ['Russian organizations']}],
 'title': 'WinRAR Zero-Day Path Traversal Vulnerability (CVE-2025-8088) '
          'Exploited in Targeted Phishing Campaigns',
 'type': ['Zero-day exploit',
          'Path traversal vulnerability',
          'Arbitrary code execution',
          'Phishing campaign'],
 'vulnerability_exploited': 'CVE-2025-8088 (WinRAR path traversal flaw in '
                            'Windows versions < 7.13)'}
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