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The vulnerability resides in the /en-US/static/ web endpoint within Splunk Enterprise and Splunk Cloud Platform. This endpoint serves static resources but lacks proper input sanitization for HTTP request elements. An unauthenticated attacker can craft HTTP requests containing ANSI escape code sequences. These sequences are special character combinations that control text formatting in terminal environments, such as changing colors or moving the cursor. When the vulnerable Splunk instance processes a request to this endpoint, it logs details like the User-Agent string or URL parameters without filtering these codes. The ANSI sequences are then written directly into the log files. Subsequently, when these log files are viewed using terminal-based tools or certain log management systems that interpret ANSI codes, the embedded sequences execute. This execution can manipulate the visual display of the log data. For instance, codes can be used to overwrite existing log lines, insert forged entries, or hide sensitive information by changing text color to blend with the background. This attack poisons the log integrity without requiring authentication. The flaw allows obfuscation of malicious activities recorded in logs, potentially impacting forensic analysis and security monitoring. The CVSS vector indicates network attack scope, low attack complexity, and no user interaction required. The impact is solely on data integrity within the logs, not confidentiality or availability. Fixed versions address this by validating and stripping ANSI escape sequences from request data before logging.
Platform: Splunk Enterprise & Cloud
Version: Multiple vulnerable versions
Vulnerability: ANSI escape code injection
Severity: MEDIUM
Date: 12/03/2025
Prediction: Patch expected 2025-12-10
What Undercode Say:
Analytics:
curl -H "User-Agent: \033[31mINJECTED\033[0m" $SPLUNK_URL/en-US/static/
curl "$SPLUNK_URL/en-US/static/?fake=\033[2J\033[H"
cat > exploit.sh << 'EOF' !/bin/bash TARGET="$1" curl -k -H "X-Forwarded-For: \033[32;1m[bash]\033[0m" $TARGET EOF
How Exploit:
Craft HTTP requests with ANSI sequences targeting the /en-US/static/ endpoint to corrupt log files viewed in terminals.
Protection from this CVE:
Upgrade to patched versions. Implement log sanitization filters. Restrict endpoint access.
Impact:
Log integrity compromise. Obscured security events. Reduced detection capability.
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Sources:
Reported By: nvd.nist.gov
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