Windows Machine Hacked With CVE-2024-49138 | Letsdefend SOC335 | SOC Training

In this post , we investigate a Windows machine that was compromised using a privilege escalation vulnerability (CVE-2024-49138). The attacker successfully exploited this weakness to gain full control over the system. We used letsdefend platform to identify IOCs and perform SOC analysis.

Incident Overview

The analyst investigates a hacked Windows machine where an attacker successfully exploited the CVE-2024-49138 vulnerability, leading to privilege escalation.

Alert Analysis: The SOC analyst identifies an alert named “SOC 335 CVE 2024 Exploitation Detected” on the dashboard and begins analyzing the process name mismatch (SvcHost typo) as a suspicious indicator.

Investigation Steps

1. Identifying the Alert:
   • Security software flagged a potential exploitation attempt.
   • The alert details revealed a suspicious process: SVOhost.exe (a typo of the legitimate svchost.exe).
2. Analyzing the Suspicious Process:
   • The parent process was PowerShell, which is unusual (normally, it should be services.exe).
   • The file path was under the Temp directory instead of System32, another red flag.
3. Tracing the Attack Path:
   • The attacker used RDP (Remote Desktop Protocol, port 3389) to access the victim machine.
   • Failed login attempts were detected before a successful login using the username Victor.
   • Once inside, the attacker executed PowerShell commands to check privileges and download a malicious file from an Amazon S3 bucket.
4. Malware Analysis:
   • The malware (“ServiceInstaller.zip”) was extracted in the Temp folder.
   • The payload, SVOhost.exe, was executed but did not establish an outgoing connection to a C2 server (command and control).
5. Confirming Indicators of Compromise (IoCs):
   • Hash of the malware file
   • Attacker’s IP address
   • C2 (command-and-control) IP address
   • Malicious download URL
6. Final Steps:
   • The security team marked the case as a confirmed attack (true positive).
   • The alert was closed, and security measures were recommended.

Using Powershell For Persistence & Post Exploitation

PowerShell played a critical role in the attack by being used for post-exploitation activities, allowing the attacker to establish persistence and execute commands on the compromised system. Here’s how it was leveraged:

1. Privilege Enumeration:
   • After gaining access through RDP brute force, the attacker immediately opened PowerShell and executed whoami /priv to check current user privileges.
   • This helped determine if they already had admin rights or needed further privilege escalation.
2. Downloading and Executing Malware:
   • The attacker used Invoke-WebRequest, a built-in PowerShell command, to download a malicious ZIP file (service_installer.zip) from an Amazon S3 bucket.
   • The file was extracted using 7-Zip with a predefined password (infected).
   • The extracted file contained a fake Windows system process (SVOHost.exe), which was then executed.
3. Persistence and Evasion:
   • The malware was hidden in the Temp directory, mimicking a system process but with a typo (SVOHost instead of SvcHost).
   • The parent process was identified as PowerShell, further confirming it was executed manually by the attacker.
4. No Immediate C2 Connection Detected:
   • While the malware executed successfully, no direct connection to a Command & Control (C2) server was detected in the network logs.
   • The analyst checked outbound network connections but found no communication to the suspected C2 address (ending in .141).
   • This suggests that the attacker may have used another method to exfiltrate data or was waiting for manual commands.

Insights Based on Numbers

• 3389 – The attack exploited Remote Desktop Protocol (RDP) to gain access.
• 235 PM – The precise timestamp of initial attacker login, correlating with execution logs.
• 141 – The last digits of the C2 server’s IP address, used to check for outbound connections.
• 51 security flags – VirusTotal marked the malware as malicious, confirming its threat level.

CVE-2024-49138

CVE-2024-49138 is a high-severity elevation of privilege vulnerability affecting the Windows Common Log File System (CLFS) driver. This flaw allows attackers with local access to escalate their privileges to administrative levels, potentially gaining full control over the affected system. The vulnerability has been actively exploited in the wild, as reported by cybersecurity authorities.

Key Details:

• CVE Identifier: CVE-2024-49138
• CVSS Score: 7.8 (High)
• Attack Vector: Local access required
• Impact: Allows attackers to execute code with elevated privileges

How Privilege Escalation Works

Privilege escalation is a critical concept in cybersecurity where an attacker gains higher access rights than initially permitted. This allows them to control a system, install malware, steal data, or even disable security measures.

1️⃣ Types of Privilege Escalation

A) Vertical Privilege Escalation (Gaining Admin/Root Access)

This happens when a low-privileged user (e.g., a regular employee account) gains administrative or system-level privileges.

🔹 Example:

• A hacker exploits a Windows vulnerability to run commands as SYSTEM (the most powerful user).
• They bypass security restrictions and get full control over the machine.

🛠 How it’s Done:
✔ Exploiting OS vulnerabilities (e.g., CVE-2024-49138 from the video)
✔ Bypassing UAC (User Account Control)
✔ Gaining access to password hashes & cracking them

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B) Horizontal Privilege Escalation (Accessing Other Users’ Data)

This happens when an attacker stays at the same privilege level but accesses another user’s account.

🔹 Example:

• A normal user hijacks another employee’s session and reads their emails.
• A hacker finds a flaw in a web application to access other users’ sensitive data.

🛠 How it’s Done:
✔ Session Hijacking
✔ Exploiting web vulnerabilities (e.g., Insecure Direct Object References – IDOR)
✔ Misconfigured permissions (files/folders mistakenly shared with all users)

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2️⃣ How Attackers Exploit Privilege Escalation Vulnerabilities

Step 1: Gaining Initial Access

• Phishing (stealing credentials)
• Exploiting weak passwords
• Malware (keyloggers, backdoors)

Step 2: Finding Privilege Escalation Paths

• Checking OS version & installed software for known vulnerabilities
• Looking at misconfigured permissions (e.g., files with Everyone access)
• Exploiting insecure processes (e.g., running PowerShell as admin)

Step 3: Executing the Exploit

• Using an unpatched vulnerability to elevate privileges
• Injecting malicious DLLs into system processes
• Stealing and reusing authentication tokens

Step 4: Maintaining Access

• Creating a hidden admin account
• Installing a rootkit or keylogger
• Disabling antivirus/security tools

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3️⃣ Real-World Privilege Escalation Examples

Windows 10 UAC Bypass – Attackers exploited a flaw in Windows User Account Control (UAC) to run malware as admin.

Linux Dirty Pipe (CVE-2022-0847) – Allowed attackers to overwrite sensitive files and gain root access.

Web Apps (IDOR) – A bug in a healthcare website let users view other patients’ medical records by changing the URL.

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4️⃣ How to Protect Against Privilege Escalation

✅ Keep systems updated (patch vulnerabilities ASAP)
✅ Use least privilege principles (limit user permissions)
✅ Monitor logs for unusual activity (e.g., PowerShell running unusual scripts)
✅ Use strong authentication methods (MFA, password managers)
✅ Restrict access to sensitive files (no Everyone permissions)

Video Walkthrough

Key Takeaways

✅ Typos in process names can be a sign of malware.
✅ PowerShell as a parent process for system services is suspicious.
✅ Checking login attempts helps track how attackers gained access.
✅ Network connections and logs are critical for tracing the attack.
✅ Sandbox analysis tools (VirusTotal, ANY.RUN) confirm malicious behavior.