CVE-2025-66374

Executive Summary

CVE-2025-66374 is a privilege escalation vulnerability in CyberArk Endpoint Privilege Manager (EPM) Agent, affecting versions through 25.10.0. A local authenticated user can exploit this flaw to elevate their privileges by abusing the policy elevation mechanism for an Administration task. This allows an attacker to gain unauthorized administrative control over the endpoint, bypassing the intended security controls of the EPM solution. The vulnerability has a CVSS score of 0.0 (unscored) and no public exploit or patch is currently available.

Supply Chain & Package Security

This vulnerability is not related to an open-source package manager (NPM, PyPI, Go, Ruby). It is a proprietary software component from CyberArk. The risk is limited to organizations that have deployed the CyberArk EPM Agent on their endpoints.

CVSS Breakdown & Threat Level

CVSS Score: 0.0 (Unscored) Vector: UNKNOWN

The CVSS score is currently 0.0, indicating that the NVD has not yet assigned a severity rating. However, based on the nature of the vulnerability (local privilege escalation), the likely impact is high. An attacker with local access can gain full administrative control, leading to complete compromise of the endpoint.

Threat Level: High (based on impact, despite low attack complexity and local access requirement).

Deep Dive & Mechanics

The vulnerability resides in the CyberArk Endpoint Privilege Manager Agent's policy elevation mechanism. The EPM agent is designed to allow certain applications or tasks to run with elevated privileges based on predefined policies. However, a flaw in the handling of "Administration tasks" allows a local user to bypass these policies and elevate their own privileges.

Technical Breakdown:

1. Policy Elevation Mechanism: The EPM agent uses a policy engine to determine which processes can be elevated. This is typically based on file path, hash, or digital signature.
2. Administration Task Handling: The agent has a special category for "Administration tasks" – tasks that require administrative rights for system management.
3. Flaw: The vulnerability allows a local user to craft a request or manipulate the policy evaluation to make the agent believe that a user-controlled process is a legitimate "Administration task." This results in the agent granting the process elevated privileges (e.g., SYSTEM or Administrator).
4. Privilege Escalation: Once the attacker's process runs with elevated privileges, they can execute arbitrary commands, install malware, disable security controls, or persist on the system.

The exact mechanism is not publicly disclosed, but it likely involves:

• Policy Bypass: Exploiting a logic error in the policy matching algorithm.
• Token Manipulation: Intercepting or forging the security token used for elevation.
• Race Condition: Exploiting a time-of-check to time-of-use (TOCTOU) vulnerability in the elevation process.

Vulnerable vs. Patched Code

Since no patch is available, a direct code comparison is not possible. However, the vulnerability is present in CyberArk EPM Agent versions through 25.10.0. The fix would likely involve:

• Stricter Policy Validation: Ensuring that only pre-approved, signed binaries can be elevated as "Administration tasks."
• Integrity Checks: Verifying the integrity of the process requesting elevation (e.g., checking digital signatures, parent process chain).
• Token Hardening: Using more secure token handling to prevent impersonation or forgery.

Vulnerable Code (Conceptual):

// Vulnerable: No integrity check on the requesting process
if (IsAdministrationTask(request)) {
    GrantElevatedPrivileges(request.process);
}

Patched Code (Conceptual):

// Patched: Verify process integrity before elevation
if (IsAdministrationTask(request) && VerifyProcessIntegrity(request.process)) {
    GrantElevatedPrivileges(request.process);
}

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Local access to a system running CyberArk EPM Agent <= 25.10.0.
• Ability to execute code as a standard user.

Exploitation Steps:

1. Reconnaissance: Identify the EPM agent version and running services.

   Get-WmiObject -Class Win32_Product | Where-Object {$_.Name -like "*CyberArk*"}
   

2. Craft Exploit: Create a simple executable that requests elevation as an "Administration task." This could be done by:

   • Modifying the registry or configuration files to add a new policy entry.
   • Using a known technique to impersonate a trusted process.
   • Exploiting a race condition in the policy evaluation.

   Example (Conceptual PowerShell):

   # This is a conceptual example. Actual exploit may differ.
   $task = New-Object -ComObject "CyberArk.EPM.Task"
   $task.Type = "Administration"
   $task.Command = "cmd.exe /c whoami"
   $task.Execute()
   

3. Execute Exploit: Run the crafted executable. If successful, the command will run with elevated privileges (e.g., SYSTEM).

4. Post-Exploitation: Once elevated, the attacker can:

   • Create a new local admin user.
   • Disable security software.
   • Install a backdoor.
   • Dump credentials.

Blue Team (Detection & Prevention)

Detection:

• Monitor Process Creation: Look for unusual processes being created with elevated privileges, especially those not matching known administrative tasks.
• Audit Policy Changes: Monitor for changes to the EPM policy configuration files or registry keys.
• Log Analysis: Review EPM agent logs for failed or suspicious elevation requests.

Prevention:

• Apply Patches: Once a patch is released, apply it immediately.
• Restrict Local Access: Limit the number of users with local access to endpoints.
• Application Control: Use additional application control solutions (e.g., AppLocker, WDAC) to restrict execution of unauthorized binaries.
• Principle of Least Privilege: Ensure users have the minimum privileges necessary.

Indicators of Compromise (IOCs)

File IOCs:

• Suspicious executables in temporary directories (e.g., %TEMP%\*.exe).
• Modified EPM policy files (e.g., C:\ProgramData\CyberArk\EPM\Policy.xml).

Process IOCs:

• cmd.exe or powershell.exe spawned by the EPM agent (AIMAgent.exe or similar) with elevated privileges.
• Unusual parent-child process relationships (e.g., explorer.exe spawning cmd.exe as SYSTEM).

Network IOCs:

• Outbound connections from the EPM agent to unknown IP addresses (if the exploit downloads additional payloads).

Registry IOCs:

• New or modified registry keys under HKLM\SOFTWARE\CyberArk\EPM\Policies.

Log IOCs:

• Windows Event ID 4688 (Process Creation) showing a process with TokenElevationType = %%1937 (Full Token) spawned by a non-admin user.
• EPM agent logs showing ElevationGranted events for unknown or suspicious tasks.

Detection Engineering

YARA Rule

rule CVE_2025_66374_CyberArk_EPM_Elevation {
    meta:
        description = "Detects potential exploitation of CVE-2025-66374 in CyberArk EPM Agent"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-66374"
        hash = "unknown"
    strings:
        $s1 = "CyberArk.EPM.Task" wide ascii nocase
        $s2 = "Administration" wide ascii nocase
        $s3 = "GrantElevatedPrivileges" wide ascii nocase
        $s4 = "AIMAgent.exe" wide ascii nocase
    condition:
        (uint16(0) == 0x5A4D) and // MZ header
        (1 of ($s1, $s2, $s3) or $s4)
}

Sigma Rule

title: CyberArk EPM Agent Privilege Escalation (CVE-2025-66374)
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects potential exploitation of CVE-2025-66374 via process creation anomalies
author: Valters IT
date: 2025-04-10
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2025-66374
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\AIMAgent.exe'
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
            - '\wmic.exe'
        TokenElevationType: '%%1937'  # Full Token
    condition: selection
falsepositives:
    - Legitimate administrative tasks triggered by EPM policy
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-66374 CyberArk EPM Agent Potential C2 Beacon"; flow:to_server,established; content:"|00 00 00 00|"; depth:4; content:"CyberArk"; nocase; distance:0; within:100; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate Affected Systems: If possible, isolate systems running the vulnerable EPM agent version until a patch is applied.
2. Restrict Local Access: Limit the number of users who can log on locally to affected endpoints.
3. Monitor for IOCs: Actively monitor for the IOCs listed above.

Long-Term Remediation:

1. Apply Patch: Monitor CyberArk's security advisories and apply the official patch as soon as it is released.
2. Update EPM Agent: Upgrade to a patched version of the CyberArk EPM Agent.
3. Review Policies: Review and harden EPM policies to ensure only necessary tasks are allowed elevation.
4. Implement Defense in Depth: Use additional security controls such as application whitelisting, endpoint detection and response (EDR), and network segmentation.

Workaround (if patch is unavailable):

• Disable the "Administration task" elevation feature in the EPM policy if it is not required.
• Use a custom script to monitor and block suspicious elevation requests.

Valters IT