CVE-2024-11035

Executive Summary

CVE-2024-11035 is a low-severity information disclosure vulnerability affecting the Carbon Black Cloud Windows Sensor prior to version 4.0.3. The vulnerability allows a local attacker with low privileges to leak sensitive information from the sensor process. With an EPSS score of 0.0% and no known public exploits, this vulnerability currently poses a minimal risk to most environments. However, given the sensitive nature of endpoint detection and response (EDR) sensor data, organizations should prioritize patching to prevent potential reconnaissance by local adversaries.

Supply Chain & Package Security

This vulnerability is not related to any open-source package ecosystem (NPM, PyPI, Go, Ruby). It affects a proprietary Windows binary distributed by VMware Carbon Black.

CVSS Breakdown & Threat Level

• CVSS Score: 2.5 (Low)
• Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
• 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.
• Scope: Unchanged (S:U) – The vulnerability does not affect other components.
• Confidentiality Impact: Low (C:L) – Limited sensitive information may be exposed.
• Integrity Impact: None (I:N) – No data modification is possible.
• Availability Impact: None (A:N) – No denial of service.

Threat Level: Low. The vulnerability requires local access and low privileges, and no public exploits exist.

Deep Dive & Mechanics

The Carbon Black Cloud Windows Sensor is a kernel-mode driver and user-mode service that monitors system activity for threat detection. The information leak vulnerability (CWE-200) stems from improper handling of memory buffers or log files that may contain sensitive data such as process command lines, file paths, or configuration details.

Root Cause: The sensor, prior to version 4.0.3, does not adequately sanitize or restrict access to internal data structures. A local attacker can leverage standard Windows API calls or process memory dumps to extract information that should be protected.

Attack Scenario:

1. An attacker gains low-privileged access to a Windows endpoint (e.g., via phishing or credential theft).
2. The attacker enumerates running processes and identifies the Carbon Black sensor (e.g., cb.exe or RepMgr.exe).
3. Using tools like Process Explorer, WinDbg, or a custom memory reader, the attacker reads process memory or log files.
4. Sensitive data such as API keys, internal IP addresses, or endpoint telemetry is extracted.

Impact: While the CVSS score is low, the leaked information could aid in further attacks, such as lateral movement or privilege escalation.

Vulnerable vs. Patched Code

Since the exact code fix is proprietary, the following is a conceptual comparison based on typical information leak patches.

Vulnerable Code (Pre-4.0.3):

// Pseudocode for logging function
void LogEvent(const char* eventData) {
    // Writes event data to a world-readable log file
    FILE* log = fopen("C:\\ProgramData\\CarbonBlack\\logs\\sensor.log", "a");
    fprintf(log, "%s\n", eventData);
    fclose(log);
}

Patched Code (4.0.3+):

// Pseudocode for patched logging function
void LogEvent(const char* eventData) {
    // Sanitize sensitive fields before logging
    char* sanitizedData = SanitizeSensitiveData(eventData);
    // Write to a restricted log file with proper ACLs
    FILE* log = fopen("C:\\ProgramData\\CarbonBlack\\logs\\sensor.log", "a");
    if (log) {
        fprintf(log, "%s\n", sanitizedData);
        fclose(log);
    }
    free(sanitizedData);
}

Key Changes:

• Input sanitization to remove sensitive fields (e.g., API tokens, passwords).
• Restricted file permissions on log directories.
• Memory buffer clearing after use.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Local access to a Windows system with Carbon Black Cloud Windows Sensor < 4.0.3.
• Low-privileged user account.

Steps:

1. Identify Sensor Process:

   Get-Process -Name "cb", "RepMgr" | Select-Object Id, ProcessName
   

2. Dump Process Memory: Use procdump from Sysinternals:

   procdump -ma <PID> c:\temp\sensor.dmp
   

3. Extract Sensitive Strings:

   Select-String -Path c:\temp\sensor.dmp -Pattern "api_key|token|secret|password"
   

4. Check Log Files:

   type "C:\ProgramData\CarbonBlack\logs\*.log" | findstr /i "api_key token"
   

Expected Outcome: Leaked API keys or internal configuration data.

Blue Team (Detection & Response)

Detection Steps:

1. Monitor for unauthorized process memory access:

   • Event ID 10 (ProcessAccess) in Sysmon.
   • Look for procdump.exe or Taskmgr.exe accessing cb.exe.

2. Audit log file access:

   • Enable SACL on C:\ProgramData\CarbonBlack\logs\ for Everyone group.

3. Check for unusual strings in logs:

   Get-WinEvent -LogName "Microsoft-Windows-Sysmon/Operational" | Where-Object { $_.Id -eq 10 -and $_.Properties[6].Value -like "*cb.exe*" }
   

Hunting Query (KQL):

DeviceProcessEvents
| where FileName in~ ("procdump.exe", "procdump64.exe")
| where ProcessCommandLine contains "cb.exe" or ProcessCommandLine contains "RepMgr.exe"

Indicators of Compromise (IOCs)

• File Hashes (SHA256): None available (no public samples).
• Process Names: cb.exe, RepMgr.exe, RepMgr64.exe
• Log Paths: C:\ProgramData\CarbonBlack\logs\sensor.log
• Network Indicators: None (local vulnerability only).
• Registry Keys: HKLM\SOFTWARE\CarbonBlack\SensorVersion (check version < 4.0.3)

Detection Engineering

YARA Rule

rule CVE_2024_11035_InfoLeak {
    meta:
        description = "Detects potential information leak from Carbon Black sensor memory dumps"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-11035"
    strings:
        $s1 = "api_key" ascii wide nocase
        $s2 = "token" ascii wide nocase
        $s3 = "secret" ascii wide nocase
        $s4 = "password" ascii wide nocase
        $s5 = "cb.exe" ascii wide nocase
    condition:
        any of ($s1, $s2, $s3, $s4) and $s5
}

Sigma Rule

title: Carbon Black Sensor Memory Access by Suspicious Tools
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects tools like procdump accessing Carbon Black sensor process memory
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2024-11035
author: Valters IT
date: 2025/04/10
logsource:
    product: windows
    service: sysmon
detection:
    selection:
        EventID: 10
        TargetImage|endswith:
            - '\cb.exe'
            - '\RepMgr.exe'
            - '\RepMgr64.exe'
        SourceImage|endswith:
            - '\procdump.exe'
            - '\procdump64.exe'
            - '\Taskmgr.exe'
    condition: selection
falsepositives:
    - Legitimate debugging by administrators
level: medium

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2024-11035 - Potential Carbon Black Sensor Data Exfiltration"; flow:to_server,established; content:"api_key"; nocase; content:"token"; nocase; within:100; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Patch: Upgrade Carbon Black Cloud Windows Sensor to version 4.0.3 or later.

   • Download from VMware Carbon Black console.
   • Deploy via group policy or endpoint management tool.

2. Workaround: Restrict local access to the sensor process and logs:

   icacls "C:\ProgramData\CarbonBlack\logs" /inheritance:r /grant "SYSTEM:(OI)(CI)F" "Administrators:(OI)(CI)F"
   

3. Monitor: Enable Sysmon Event ID 10 and alert on suspicious process access.

Long-term:

• Implement least privilege for local users.
• Use application whitelisting to block tools like procdump.
• Regularly audit EDR sensor versions.

Valters IT – Securing your digital frontier.