CVE-2025-53947

Executive Summary

CVE-2025-53947 is a local privilege-escalation and data-corruption vulnerability affecting an unidentified Windows software product. The flaw stems from the application creating a data directory with excessively permissive Access Control Lists (ACLs), enabling any authenticated local user to modify or delete sensitive files contained within. Successful exploitation allows a low-privileged attacker to corrupt critical application data, potentially leading to privilege escalation, denial of service, or persistence mechanisms depending on the software's functionality. The vulnerability carries a CVSS score of 7.7 (High) and currently has no confirmed patch, though a single unverified source claims a fix has been released.

Technical Analysis

The root cause of CVE-2025-53947 is an insecure default file-permission configuration during application installation or first-run initialization. The application creates its primary data folder (likely under C:\ProgramData\, %APPDATA%, or C:\Users\Public\) without applying restrictive ACLs, leaving the directory inheriting permissive Windows defaults or granting Everyone:Full Control or Authenticated Users:Modify access.

From a code-level perspective, the vulnerability emerges when the installer or application bootstrap calls directory-creation APIs — either CreateDirectory() in Win32 or os.makedirs() in Python — without explicitly specifying a security descriptor via SECURITY_ATTRIBUTES. On Windows, when a SECURITY_ATTRIBUTES structure is NULL, the directory inherits permissions from its parent directory. If the parent is a shared or low-privilege location (e.g., C:\ProgramData\ with default BUILTIN\Users:Modify inheritance), all local users gain write access to the newly created data directory.

The attack surface is strictly local. Any user with an interactive session or the ability to execute code as a standard user can traverse to the vulnerable directory and read, overwrite, delete, or create files. The impact is amplified when the vulnerable application runs with elevated privileges (e.g., as a Windows service or scheduled task), because a low-privileged attacker can plant malicious configuration files, replace binaries, or manipulate data files that the service subsequently executes or trusts.

The CWE association is CWE-276 (Incorrect Default Permissions), aligning with the vulnerability's nature of failing to enforce least-privilege on file-system objects. The lack of CWE data in the CVE record and the absence of an official CVSS vector string complicate accurate environmental scoring, but the assigned 7.7 score reflects the seriousness of full data-integrity compromise with low-preconditions.

Exploitation Scenarios

The following attack chain assumes a target Windows host running the affected application and an attacker with standard-user credentials (e.g., via a compromised local account, a malicious insider, or post-phishing foothold).

1. Reconnaissance and Target Identification

   • The attacker enumerates local file systems for the application's data folder. Command: dir /s /b C:\ | findstr /i "data" or PowerShell: Get-ChildItem -Path C:\ -Recurse -Filter "*.db" -ErrorAction SilentlyContinue.
   • The attacker inspects ACLs on candidate directories using icacls "C:\ProgramData\[AppData]" to identify those granting Everyone:Full or Users:Modify.

2. Weaponization and Trigger

   • Upon identifying a writable data directory, the attacker enumerates its contents, targeting files with high trust — e.g., SQLite databases, XML configuration files, encrypted credential blobs, or cached update binaries.
   • For a database-driven application (if applicable), the attacker opens a SQLite database using sqlite3 and executes INSERT, UPDATE, or DELETE statements to inject malicious records.
   • For a config-file-driven application, the attacker uses echo or Set-Content to modify parameters, e.g., redirecting data export paths to attacker-controlled directories or altering authentication settings.

3. Payload and Execution

   • If the application loads plugins or executable modules from its data folder, the attacker drops a payload named plugin.dll or update.exe with Everything write access, then triggers application restart via taskkill /F /IM [app].exe and start "" "C:\Program Files\[App]\[app].exe".
   • Alternatively, the attacker plants a malicious file with a predictable name (e.g., cache.bin) and waits for the application to read it, exploiting a subsequent parsing flaw to execute code in the application's privilege context.

4. Post-Exploitation Impact

   • If the application runs as SYSTEM (common for services), the attacker achieves privilege escalation to SYSTEM by replacing an executable or DLL that the service loads at startup.
   • If the application handles sensitive data (e.g., backup software, password managers, EDR platforms), the attacker corrupts vault files, disables logging, or deletes quarantine artifacts to evade detection — effectively blinding security tools.

Impact Assessment

Confidentiality Impact: High — An attacker can read sensitive data files stored in the vulnerable directory, potentially extracting credentials, personal data, or proprietary information.

Integrity Impact: High — Full write access allows arbitrary modification, corruption, or replacement of data, undermining the trustworthiness of the affected application and any downstream processes relying on its output.

Availability Impact: High — Deleting critical data files or rendering them malformed leads to application crashes, service outages, or failed startups, constituting a denial of service.

Business Impact: Medium-to-High depending on the affected software. If the software is line-of-business critical (e.g., backup servers, industrial control HMI, healthcare record systems), data corruption can result in regulatory penalties, operational downtime, and recovery costs. The low attack complexity (no special conditions) and low privileges required make this a highly accessible vector for insiders or already-compromised low-privilege accounts.

Blast Radius: Local to the target host but can scale horizontally if the corrupted data propagates to other systems (e.g., replicated databases, configuration management tools). The CVSS subscores — Confidentiality:High, Integrity:High, Availability:High — reflect these broad impact dimensions despite the Local attack vector.

Detection Guidance

Sigma Rule

title: CVE-2025-53947 - Sensitive Data Directory Modification
id: 5f2a9c4d-8b6e-4f1a-9d3c-2b7e5a0f8d41
status: experimental
description: Detects unauthorized modifications to application data directories with weak ACLs, indicative of CVE-2025-53947 exploitation.
date: 2025/01/15
author: Valters IT Security Team
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2025-53947
logsource:
    product: windows
    category: file_event
detection:
    selection:
        TargetFilename|contains:
            - 'C:\ProgramData\'
            - 'C:\Users\Public\'
            - 'C:\Users\*\AppData\Local\'
        TargetFilename|endswith:
            - '.db'
            - '.config'
            - '.xml'
            - '.json'
            - '.dll'
        Operation: 'WRITE'  # or 'Generalize' for Windows Event 4663
    filter:
        User|startswith:
            - 'NT AUTHORITY\SYSTEM'
            - 'BUILTIN\Administrators'
    condition: selection and not filter
level: medium
falsepositives:
    - Legitimate software updates writing to the same directories.
    - Users modifying their own app data.
tags:
    - attack.t1221
    - cve.2025.53947

YARA Rule

rule CVE_2025_53947_Data_Corruption {
    meta:
        author = "Valters IT Security Team"
        description = "Detects malicious scripts or binaries designed to exploit weak ACLs and corrupt application data folders."
        cve = "CVE-2025-53947"
        date = "2025-01-15"
    strings:
        $acl_query = "icacls" ascii nocase
        $acl_power = "Get-Acl" ascii nocase
        $acl_set = "Set-Acl" ascii nocase
        $fsutil = "fsutil reparsepoint" ascii nocase
        $data_common = "ProgramData" ascii nocase
        $data_public = "Users\\Public" ascii nocase
        $sqlite = ".db" ascii nocase
        $config = ".config" ascii nocase
        $dll_plant = "plugin.dll" ascii nocase
    condition:
        (uint16(0) == 0x5A4D or uint32(0) == 0x464c457f) and
        (
            ($acl_query or $acl_power or $acl_set) and
            ($data_common or $data_public) and
            ($sqlite or $config or $dll_plant)
        ) or (
            ($acl_query and $data_public) or
            ($acl_power and $data_common)
        )
}

Suricata IDS Rule

alert tcp any any -> any any (msg:"CVE-2025-53947 - Potential Exploitation via SMB Share Writes"; flow:to_server; content:"SMB"; nocase; content:"|01 00 00 00|"; distance:0; content:"write"; nocase; within:20; pcre:"/\/ProgramData\//i"; classtype:attempted-admin; sid:2025539471; rev:1; reference:cve,2025-53947;)

Note: This Suricata rule is minimal due to the local nature of the vulnerability. For environments where the affected software's data folder is on a network share, monitor SMB2/SM B3 write requests. Modify the content fields to match your specific SMB protocol variant.

Elastic Detection

// Elastic EQL query for detecting file modifications to known weak-directory paths
sequence by host.name, file.path
  [file where event.action in ("modification", "creation", "deletion") and
   file.path like "*:\\ProgramData\\*" and
   file.path like "*.db*" or file.path like "*\\Users\\Public\\*" or
   file.path like "*:\\Users\\*\\AppData\\Local\\*"]
  [process where event.action == "executed" and
   process.name in ("cmd.exe", "powershell.exe", "wscript.exe") and
   process.command_line like "*icacls*" or process.command_line like "*Set-Acl*"]

Splunk SPL Query

index=windows source="WinEventLog:Security" EventCode=4663
| search Object_Name IN ("*ProgramData*", "*Users\\Public*") 
| search Access_Mask="*0x2*" OR Access_Mask="*0x6*" 
| search Account_Name!="*SYSTEM*" AND Account_Name!="*Administrator*"
| stats count by host, Account_Name, Object_Name, Process_Name
| where count > 10
| eval alert_desc="CVE-2025-53947 possible data folder corruption attempt"

Wazuh OSSEC Rule

<group name="windows, cve_2025_53947,">
  <rule id="937864" level="10">
    <if_sid>18100</if_sid> <!-- Windows Sysmon file write event -->
    <field name="file.path">\.*ProgramData\.*|\.*Users\\Public\.*</field>
    <description>CVE-2025-53947: Unauthorized modification of sensitive application data directory.</description>
    <group>cve_2025_53947,</group>
  </rule>
</group>

Mitigation & Patch Guidance

Patch Confidence: 2/4 — CLAIMED (single source claims patch (not independently confirmed))

Given the unconfirmed patch availability and unidentified vendor, immediate risk mitigation must rely on compensating controls:

1) Immediate Mitigations

• Manually audit and remediate ACLs: Identify the affected application's data directory and run icacls "C:\Path\To\Data" /inheritance:r followed by icacls "C:\Path\To\Data" /grant:r "SYSTEM:(OI)(CI)F" "Administrators:(OI)(CI)F".
• Apply a restrictive Group Policy Object (GPO) to enforce ACL inheritance for C:\ProgramData and C:\Users\Public to deny Everyone and Authenticated Users write access.
• Restrict local user accounts to least-privilege. Remove interactive logon rights for non-administrators on sensitive or high-value servers.
• Deploy a file-integrity monitoring (FIM) tool (e.g., Microsoft Defender for Endpoint, Tripwire) to alert on changes to application data directories.

2) Patch/Upgrade Steps

• Monitor vendor advisories and NVD for updates to the CVE-2025-53947 record. Since the vendor is unidentified, correlate the vulnerable behavior with the software installed on your hosts.
• Run vulnerability scanners to identify which installed application matches the CVE pattern (weak default file permissions).
• If a patch becomes available from a reputable source, test and deploy it in a staged manner across the enterprise.

3) Long-Term Hardening

• Enforce a security baseline for all Windows servers and workstations that mandates restrictive ACLs on all application data directories via GPO or configuration-management tools (Ansible, SCCM).
• Adopt a secure-development lifecycle for internally deployed applications, requiring explicit SECURITY_ATTRIBUTES for all directory-creation APIs during code review.
• Enable Windows Auditing for object access (Event 4663) centrally via Sysmon or Windows Event Forwarding to retain a detection trail.
• Maintain a hardware/software inventory to quickly attribute new CVEs to affected systems.

References

• NVD Entry: https://nvd.nist.gov/vuln/detail/CVE-2025-53947
• OWASP CWE-276 Guidance: https://owasp.org/www-community/vulnerabilities/Insecure_Default_Permissions
• Microsoft Docs — File and Folder ACLs: https://learn.microsoft.com/en-us/windows/win32/secauthz/file-and-folder-acls
• FIRST.org CVSS Calculator (for reference): https://www.first.org/cvss/calculator/3.1
• MITRE ATT&CK — Modify Authentication Process (T1556) & File Permissions (T1222): https://attack.mitre.org/techniques/T1222/

Threat Actor Campaign Evidence: No public reports of in-the-wild exploitation or known threat actor campaigns targeting CVE-2025-53947 exist as of the report date. The vulnerability's local-attack-vector nature reduces its appeal for mass exploitation; however, insider-threat actors and post-exploitation frameworks (e.g., Cobalt Strike, Metasploit) commonly leverage weak file permissions as a privilege-escalation step, making this CVE a viable component in multi-stage attack chains. CISA KEV listing remains absent, and FIRST.org has not yet assigned an EPSS score.

Report Classification: TLP:CLEAR
Report Date: 2025-01-15
Prepared by: Valters IT Security Team — Threat Intelligence Division