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CVE-2025-2783

Zero-Click Chrome Sandbox Escape via Mojo Flaw: CVE-2025-2783 Breakdown

Vulnerability Overview 

CVE ID: CVE-2025-2783  

CVE Title: Google Chrome Sandbox Escape via Mojo IPC  

Severity: High 

Exploit Status: Proof of Concept (PoC)  

Business Risk: High financial, operational, or reputational risk 

Compliance Impact: Potential impact on PCI-DSS, NIST, and GDPR compliance

Summary

CVE-2025-2783 is a sandbox escape vulnerability in Google Chrome versions before 134.0.6998.178. It exploits a flaw in Mojo IPC (Inter-Process Communication), allowing attackers to escape Chrome’s sandbox and potentially execute arbitrary code on the host system when combined with other exploits. This significantly increases the risk of full system compromise via browser-based attacks.

Urgent Actions Required

  • Immediately update Google Chrome to version 134.0.6998.178 or later.
  • Immediately update Microsoft Edge to version 134.0.3124.93 or later.
  • Scan systems to identify and remediate any vulnerable installations without delay.

Which Systems Are Vulnerable to CVE-2025-2783?

Technical Overview

  • Vulnerability Type: Remote Code Execution via Sandbox Escape
  • Affected Software/Versions:
    • Google Chrome (before v134.0.6998.177)
    • Chromium-based browsers using Mojo IPC
  • Attack Vector: Remote (typically via malicious web pages or ads)
  • CVSS Score: 8.8
  • Exploitability Score:
    • Attack Vector: Network
    • Attack Complexity: Low
    • Privileges Required: None
    • User Interaction: Required
  • Patch Availability: Yes, available3

How Does the CVE-2025-2783 Exploit Work?

CVE-2025-2783 is a serious flaw in Google Chrome on Windows that lets attackers break out of Chrome’s safe sandbox. 

Here’s how the attack works: 

How Does the CVE-2025-2783 Exploit Work?

This method is used in Operation ForumTroll phishing attacks targeting Russian media and schools. The exploit requires limited user interaction (e.g., clicking a malicious link), making it especially dangerous.

What Causes CVE-2025-2783?

Vulnerability Root Cause:

The flaw stems from insufficient validation of user-controlled input in Mojo IPC messages sent from the renderer process. Attackers can craft a malicious message that triggers unintended behavior in the browser host process, enabling code execution outside the sandbox.

How Can You Mitigate CVE-2025-2783?

If patching is delayed or not feasible: 

  • Avoid suspicious emails, links, or files, especially phishing like Operation ForumTroll.
  • Be careful on unknown or untrusted websites.
  • Use antivirus and endpoint protection to block threats.
  • Teach users to spot phishing and handle suspicious emails safely.

Ultimately, updating Chrome to version 134.0.6998.178 or later is the best way to stay safe, as it fully fixes the vulnerability.

Which Assets and Systems Are at Risk?

Asset Types Affected:

  • Endpoints – Workstations, laptops running Windows OS with vulnerable Chrome versions
  • Applications – Google Chrome browser on Windows
  • Servers – Systems running Chrome on Windows that handle web traffic or browser-based admin portals

Business-Critical Systems at Risk:

  • Browser-based admin portals and dashboards – Accessed through vulnerable Chrome versions
  • Cloud consoles – Especially those accessed via Chrome on Windows
  • User workstations – High risk if users browse malicious websites or open crafted files that exploit the vulnerability

Exposure Level:

  • Public-facing endpoints – Especially those with Chrome versions before 134.0.6998.178
  • Internal systems – At risk if users access malicious websites or open malicious files without updated Chrome versions
  • Not limited to public-facing systems – Risk occurs through user interaction with malicious content in the browser

Will Patching CVE-2025-2783 Cause Downtime?

  • Patch application impact: Low. The updates for CVE-2025-2783—Chrome versions 134.0.6998.178 and Edge version 134.0.3124.93—are small and only need a browser restart to work. There’s no need to reboot the operating system or stop major services. In managed setups, these updates can be easily installed using Group Policy Object (GPO) or Mobile Device Management (MDM) with little impact on users.
  • Mitigation (if immediate patching is not possible): While patching remains the most effective defense, temporary risk reduction can be achieved through the following steps:
    • Block access to untrusted or unknown websites, especially on important systems.
    • Limit browser use on critical devices like admin workstations and cloud dashboards.
    • Monitor Chrome/Edge behavior using EDR tools to detect unusual process activity (e.g., PowerShell spawned by browser).
    • Use browser isolation tools like remote browsers or zero-trust web gateways to lower the risk of attacks.

Note: These mitigations are partial and not a replacement for patching. CVE-2025-2783 is a sandbox escape vulnerability, meaning even trusted-looking websites or files could trigger compromise. All unpatched Chromium-based browsers on Windows remain exposed.

How Can You Detect CVE-2025-2783 Exploitation?

Exploitation Signatures:

  • Chrome or Edge spawning unusual child processes (e.g., PowerShell, cmd)
  • Abnormal IPC message patterns via the Mojo interface
  • Suspicious or unexpected handle transfers between Chrome renderer and broker processes
  • EDR rules triggering Mojo IPC misuse or sandbox violations
  • Memory access violations or crashes in Mojo-related components

MITRE ATT&CK Techniques:

  • T1203 – Exploitation for Client Execution
  • T1548 – Abuse Elevation Control Mechanism

Indicators of Compromise (IOCs/IOAs):

  • Domain: primakovreadings[.]info (used in espionage phishing campaign – Operation ForumTroll)
  • Behavioral IOCs:
    • Browser (Chrome/Edge) accessing internal ports abnormally
    • Unexpected system-level file access by sandboxed processes
    • Chrome child processes launching binaries outside normal browser behavior

Alerting Strategy:

  • Priority: High
  • Response SLA: Initial triage within 2 hours of detection
  • Contextual Focus:
    • Systems running Chrome < 134.0.6998.178 or edge < 134.0.3124.93
    • Targets of phishing campaigns (e.g., Russian media, educational/government orgs)

Remediation & Response

Patch/Upgrade Instructions:

  • Upgrade Google Chrome to version 134.0.6998.178 or later.
    Refer to Google Chrome Release Notes – March 25, 2025.2
    For managed environments, deploy updates via Group Policy Object (GPO) or Mobile Device Management (MDM) systems.
  • Microsoft Patch Guidance3
    Always validate patches in a controlled staging environment before production rollout, especially for mission-critical applications.

Mitigation Steps if No Patch:

  • Disable JavaScript for untrusted or high-risk websites
  • Restrict browser usage on critical or sensitive systems
  • Use browser isolation tools (e.g., remote browser services or Cloudflare Browser Isolation)
  • Monitor child processes spawned by Chrome using EDR/XDR solutions

Remediation Timeline:

  • Within 24 hours for internet-facing systems
  • Within 48 hours for internal or lower-risk assets

Rollback Plan:

  • Back up Chrome user profiles before deployment
  • If post-patch issues arise, revert to a prior known-stable version using enterprise software management tools

Incident Response Considerations:

  • Isolate affected systems running outdated Chrome or Edge versions if they show suspicious behavior (like unusual browser activity or unexpected processes).
  • Collect key evidence, such as:
    1. Chrome or Edge logs (especially crashes or sandbox-related errors)
    2. EDR alerts showing browsers launching PowerShell or cmd
    3. Network traffic linked to primakovreadings[.]info.
  • Check for phishing emails related to “Primakov Readings” or similar content, as used in the reported espionage campaign.
  • After cleanup, improve monitoring for signs of sandbox escapes or abnormal child processes from browsers.
  • Confirm all browsers are patched (Chrome ≥ 134.0.6998.178, Edge ≥ 134.0.3124.93) to prevent re-infection.

Compliance & Governance Notes

Standards Impacted:

  • PCI-DSS: Requirement 6.2 – Ensure all system components are protected from known vulnerabilities by installing vendor-supplied security patches within 30 days.
  • NIST SP 800-53:
    • SI-2 – Flaw Remediation
    • SI-3 – Malicious Code Protection (due to malware deployment via Chrome exploit chain)
  • ISO/IEC 27001: A.12.6.1 – Management of technical vulnerabilities
  • GDPR: Article 32 – Security of Processing, as exploitation could compromise personal or sensitive user data
  • HIPAA: Security Rule, specifically 164.308(a)(1) (Risk Management) and 164.308(a)(6) (Security Incident Procedures) — relevant for healthcare organizations using Chromium-based browsers

Audit Trail Requirement:

  • Log browser updates and patch deployments (e.g., Chrome 134.0.6998.178+ or Edge 134.0.3124.93)
  • Record any child processes launched by browsers (e.g., PowerShell or cmd from Chrome/Edge)
  • Capture EDR/AV detections linked to Mojo sandbox violations
  • Maintain browser access logs to sensitive admin portals or cloud dashboards
  • Document any alerts or indicators tied to the Operation ForumTroll phishing campaign (e.g., access to primakovreadings[.]info)

Policy Alignment:

  • Enforce timely browser patching policies across all Windows-based endpoints
  • Review and strengthen endpoint security configurations to prevent sandbox escapes
  • Update browser usage policies to limit exposure on high-risk systems (e.g., admin consoles, critical infrastructure)
  • Reinforce user awareness and training on phishing tactics involving legitimate-looking forum or event invitations

Where Can I Find More Information on CVE-2025-2783?

CVE References:

  1. ^NVD – CVE-2025-2783 – https://nvd.nist.gov/vuln/detail/CVE-2025-2783
  2. ^Google Chrome Release Blog – March 25, 2025 (Patch Announcement)
  3. ^Microsoft Security Update Guide – CVE-2025-2783 (Edge Patch Info)
  4. ^Chromium Security Overview – Sandbox and IPC (Mojo) Architecture

MITRE ATT&CK Mapping:  

CVSS Breakdown Table

MetricValue Description
Base Score8.8 (High)Reflects a high-severity impact due to sandbox escape with potential code execution
Attack VectorNetwork Exploitable remotely via malicious web pages or online content
Attack ComplexityLowNo special conditions are required beyond the crafted exploit chain
Privileges RequiredNoneExploitation does not require any privileges
User Interaction RequiredThe user must visit a malicious site or open a crafted resource
Scope ChangedThe vulnerability allows escape from a sandbox (sandbox → host context = scope change)
Confidentiality Impact HighFull sandbox escape may expose sensitive browser or system data
Integrity Impact HighThe attacker may alter system or browser-level settings or content
Availability ImpactHighExploit can be used to crash the system or browser or perform denial-of-service

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