Microsoft Windows XMLDOM ActiveX Control Information Disclosure Vulnerability (CVE-2013-7331)
Executive & SecOps Summary
SECOPS ASSESSMENTMicrosoft.XMLDOM ActiveX control and Internet Explorer on Microsoft Windows 8.1 and earlier
Remote attackers can determine the existence of local pathnames, UNC shares, intranet hostnames, and IP addresses via error code analysis
Apply the MS14-052 cumulative security update or restrict ActiveX execution in Internet Explorer
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
Apply the MS14-052 cumulative security update provided by Microsoft. For legacy systems, you can verify and enforce the installation of the required security update (such as KB2976627) using the following PowerShell commands:
# Check if the MS14-052 related hotfix is installed
Get-HotFix -Id KB2976627 -ErrorAction SilentlyContinue
# If missing, trigger Windows Update service to retrieve security patches
Set-Service -Name wuauserv -StartupType Automatic
Start-Service -Name wuauserv
$UpdateSession = New-Object -ComObject Microsoft.Update.Session
$UpdateSearcher = $UpdateSession.CreateUpdateSearcher()
$SearchResult = $UpdateSearcher.Search('IsInstalled=0 and Type=\'Software\'')2. Temporary Workaround & Hardening Configuration
If patching is not immediately feasible, disable the execution of the Microsoft.XMLDOM ActiveX control by setting the ActiveX Kill-Bit in the Windows Registry. Run the following PowerShell script with administrative privileges:
# Define registry path for Microsoft.XMLDOM ActiveX Control CLSID
$registryPath = 'HKLM:\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{2933097f-7b36-11d2-b20e-00c04f983e60}'
if (-not (Test-Path $registryPath)) {
New-Item -Path $registryPath -Force | Out-Null
}
# Set Compatibility Flags to 0x00000400 (1024) to prevent the control from running in IE
New-ItemProperty -Path $registryPath -Name 'Compatibility Flags' -Value 1024 -PropertyType DWord -Force3. Log Audit & IoC Verification Commands
Scan web gateway logs, proxy logs, or local web server access logs for suspicious patterns attempting to instantiate Microsoft.XMLDOM alongside res:// or UNC path queries.
# Search for suspicious XMLDOM and res:// patterns in web server logs
grep -rnwi 'Microsoft.XMLDOM' /var/log/nginx/ /var/log/apache2/ 2>/dev/null | grep -i 'res://'Block Kernel Privilege Escalation & Ransomware Payloads Before You Can Reboot
Protect unpatched Windows, Linux, and macOS workloads against in-memory exploitation and lateral movement with autonomous EDR.
Technical Root Cause & Exploitation Mechanics
1. Vulnerability Overview & Root Cause
This vulnerability (CVE-2013-7331) exists in the Microsoft.XMLDOM ActiveX control within Microsoft Windows. It arises due to improper handling of error messages when the control attempts to access local or network resources. By examining the specific error codes returned when loading resources via the res:// protocol or UNC paths, a remote attacker can determine whether a particular file, directory, or network share exists on the target system. This information disclosure (CWE-209) bypasses same-origin restrictions and aids in internal reconnaissance.
2. Exploitation Mechanics & Attack Scenario
An attacker hosts a malicious webpage containing crafted JavaScript and entices a user to visit it using Internet Explorer. The script instantiates the Microsoft.XMLDOM ActiveX object and calls the load() method with target paths, such as local application directories or internal network shares. Because the XML parser generates distinct error codes depending on whether a path exists (e.g., 'Access is denied' vs. 'File not found'), the script can programmatically map out the victim's local environment and intranet topology. This technique was actively exploited in the wild during 'Operation Snowman' to profile target environments before delivering secondary payloads.
3. Infrastructure & Business Impact
While this vulnerability does not directly allow remote code execution, it serves as a critical reconnaissance vector for advanced persistent threat (APT) actors. By identifying installed security software, local user directories, and internal network structures, attackers can tailor subsequent exploits with high precision. Given its history of active exploitation in watering hole attacks and its inclusion in the CISA KEV catalog, this vulnerability poses a significant risk to legacy Windows environments.
Official Vendor Advisories & References
The Microsoft.XMLDOM ActiveX control in Microsoft Windows 8.1 and earlier allows remote attackers to determine the existence of local pathnames, UNC share pathnames, intranet hostnames, and intranet IP addresses by examining error codes, as demonstrated by a res:// URL, and exploited in the wild in February 2014.
Frequently Asked SecOps Questions (CVE-2013-7331)
FAQQ1. How critical is CVE-2013-7331 and is it actively exploited in the wild?
CVE-2013-7331 is rated CVSS 6.5 (MEDIUM) with a 30-day EPSS exploitation probability of 50.2%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.
Q2. Which vendors and products are affected by CVE-2013-7331?
Primary impacted vendors include microsoft across windows, internet explorer. Scope summary: All Windows operating systems up to Windows 8.1 running Internet Explorer with the Microsoft.XMLDOM ActiveX control enabled
Q3. What temporary mitigations or workarounds exist for CVE-2013-7331 before patching?
[Mitigation] Apply the MS14-052 cumulative security update or restrict ActiveX execution in Internet Explorer Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.
Generate an Internal Engineering Notice or CISO Report for CVE-2013-7331
Instantly format this advisory into an executive CISO summary or engineering patch ticket.
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