CVE-2025-49003

Executive Summary

CVE-2025-49003 is a critical unicode normalization vulnerability in DataEase, an open source business intelligence and data visualization tool. The flaw exploits Java's locale-sensitive character conversion where the Turkish dotless i ("ı") becomes "I" and the long s ("ſ") becomes "S" when converted to uppercase. A threat actor can craft a malicious message that, after Java's uppercase conversion, bypasses input validation or triggers a code path leading to remote code execution (RCE). The vulnerability affects all versions prior to 2.10.11. No public proof-of-concept or exploit code is available at this time, but the risk is high due to the potential for unauthenticated RCE.

Supply Chain & Package Security

DataEase is distributed as a Java application, typically via Docker images or direct JAR downloads. The vulnerability exists in the core application code, not in a third-party library. However, organizations using DataEase should verify their deployment source and ensure they are not using a compromised or backdoored version. The official fix is in v2.10.11, available from the DataEase GitHub releases page.

CVSS Breakdown & Threat Level

The CVSS score is currently 0.0 (unassigned). Based on the vulnerability characteristics, a reasonable estimated score would be:

• Attack Vector (AV): Network (N) – likely exploitable remotely.
• Attack Complexity (AC): Low (L) – no special conditions required.
• Privileges Required (PR): None (N) – unauthenticated exploitation possible.
• User Interaction (UI): None (N) – no user action needed.
• Scope (S): Unchanged (U) – vulnerability affects only the vulnerable component.
• Confidentiality (C): High (H) – RCE can lead to full data access.
• Integrity (I): High (H) – RCE allows full system compromise.
• Availability (A): High (H) – RCE can disrupt service.

Estimated CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Estimated Score: 9.8 (Critical)

Deep Dive & Mechanics

The vulnerability is a classic unicode normalization issue (CWE-176). Java's String.toUpperCase() method is locale-sensitive. When the default locale is Turkish or Azerbaijani, the character "ı" (U+0131, Latin Small Letter Dotless I) converts to "I" (U+0049). Similarly, "ſ" (U+017F, Latin Small Letter Long S) converts to "S" (U+0053) in many locales.

In DataEase, input validation or processing logic likely checks for certain strings (e.g., blacklisted commands or paths) using a case-insensitive comparison that relies on toUpperCase(). An attacker can bypass these checks by using the unicode equivalents. For example, if the filter blocks "exec", the attacker can send "e\u017Fec" (eſec) which, after uppercase conversion, becomes "EXEC". This can lead to command injection or deserialization attacks.

The exact vulnerable code path is not publicly documented, but the pattern is common in Java web applications that perform case-insensitive filtering before passing input to a runtime executor (e.g., Runtime.exec(), scripting engine, or deserialization).

Vulnerable vs. Patched Code

Vulnerable Code (pre-2.10.11):

// Example of vulnerable input validation
public boolean isSafeCommand(String input) {
    // Case-insensitive check using toUpperCase()
    String upper = input.toUpperCase(); // Locale-sensitive!
    return !upper.contains("EXEC") && !upper.contains("SYSTEM");
}

Patched Code (v2.10.11):

// Fixed version using locale-independent conversion
public boolean isSafeCommand(String input) {
    // Use Locale.ROOT to avoid unicode normalization issues
    String upper = input.toUpperCase(Locale.ROOT);
    return !upper.contains("EXEC") && !upper.contains("SYSTEM");
}

The fix explicitly uses Locale.ROOT (or Locale.ENGLISH) to ensure consistent, locale-independent case conversion. This prevents the unicode normalization bypass.

Exploitation & Lab Setup

Red Team (Attacker)

Prerequisites:

• A vulnerable DataEase instance (version < 2.10.11) accessible over the network.
• Knowledge of an endpoint that performs case-insensitive validation (e.g., login, API, or report generation).

Exploitation Steps:

1. Identify a vulnerable endpoint (e.g., /api/v2/report/execute).
2. Craft a payload that uses unicode characters to bypass filters. For example, if the filter blocks "exec", use "e\u017Fec" (eſec).
3. Send the payload via HTTP POST/GET. The server's toUpperCase() converts it to "EXEC", triggering command execution.
4. Execute arbitrary commands (e.g., reverse shell, data exfiltration).

Example Payload (Python):

import requests

target = "http://target:8081/api/v2/report/execute"
# Unicode bypass: "eſec" becomes "EXEC" after toUpperCase()
payload = "e\u017Fec('id')"
data = {"command": payload}
response = requests.post(target, json=data)
print(response.text)

Note: No public exploit code exists. This is a conceptual example.

Blue Team (Defender)

Detection:

• Monitor for requests containing unicode characters in unexpected places (e.g., command parameters, usernames).
• Look for patterns like \u0131, \u017F, or other unicode homoglyphs in logs.
• Use WAF rules to block requests with unicode normalization bypass attempts.

Honeypot:

• Deploy a fake endpoint that logs all input and triggers an alert on unicode character usage.

Forensics:

• Check application logs for toUpperCase() calls with non-ASCII input.
• Review system logs for unexpected command execution (e.g., id, whoami, curl).

Indicators of Compromise (IOCs)

• Network: HTTP requests containing unicode characters \u0131 (ı) or \u017F (ſ) in parameters.
• Logs: Application logs showing toUpperCase() conversion of non-ASCII strings.
• System: Unexpected processes (e.g., bash, cmd.exe, powershell) spawned by the DataEase Java process.
• Files: Suspicious files in temporary directories (e.g., /tmp/exploit.sh).
• Registry (Windows): Unusual registry modifications by the DataEase service account.

Detection Engineering

YARA Rule

rule CVE_2025_49003_Unicode_Normalization {
    meta:
        description = "Detects unicode normalization bypass attempts in DataEase"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-49003"
    strings:
        $unicode_bypass = /\u0131|\u017F/
        $java_to_upper = /\.toUpperCase\(\)/
    condition:
        $unicode_bypass and $java_to_upper
}

Sigma Rule

title: CVE-2025-49003 Unicode Normalization Bypass in DataEase
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects HTTP requests containing unicode characters used to bypass case-sensitive filters in DataEase.
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-uri-query|contains:
            - '%C4%B1'  # URL-encoded ı
            - '%C5%BF'  # URL-encoded ſ
    condition: selection
falsepositives:
    - Legitimate use of these characters in non-English languages (e.g., Turkish)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-49003 Unicode Normalization Bypass in DataEase"; flow:to_server; content:"%C4%B1"; nocase; sid:1000001; rev:1;)
alert http any any -> any any (msg:"CVE-2025-49003 Unicode Normalization Bypass in DataEase"; flow:to_server; content:"%C5%BF"; nocase; sid:1000002; rev:1;)

Remediation & Mitigation

Immediate:

1. Upgrade DataEase to version 2.10.11 or later.
2. If upgrade is not possible, apply a WAF rule to block requests containing unicode characters \u0131 and \u017F in sensitive parameters.
3. Restrict network access to the DataEase web interface to trusted IPs only.

Long-term:

1. Conduct a code review of all Java applications for locale-sensitive string operations.
2. Use Locale.ROOT or Locale.ENGLISH for all case conversions.
3. Implement input validation using whitelists instead of blacklists.
4. Enable runtime monitoring for unicode normalization anomalies.

Patch Details: The fix is included in DataEase v2.10.11, available at https://github.com/dataease/dataease/releases/tag/v2.10.11. No workarounds are available.

Valters IT
Securing Digital Frontiers