CVE-2023-34297

Executive Summary

CVE-2023-34297 is a critical remote code execution vulnerability in Sante DICOM Viewer Pro, specifically within its JP2 file parsing functionality. The flaw is an out-of-bounds write (CWE-787) that occurs due to insufficient validation of user-supplied data when processing JP2 files. An attacker can exploit this by convincing a user to open a malicious JP2 file or visit a crafted web page, leading to arbitrary code execution in the context of the current process. With a CVSS score of 7.8, this vulnerability poses a significant risk to healthcare environments where DICOM viewers are commonly used. No public exploit or patch is currently available, making detection and mitigation critical.

CVSS Breakdown & Threat Level

• CVSS Score: 7.8 (High)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
• Attack Vector: Network (AV:N) – The vulnerability can be triggered remotely.
• Attack Complexity: Low (AC:L) – No special conditions are required.
• Privileges Required: None (PR:N) – No authentication needed.
• User Interaction: Required (UI:R) – The target must open a malicious file or page.
• Scope: Unchanged (S:U) – The exploit does not affect other components.
• Confidentiality Impact: High (C:H) – Full data access possible.
• Integrity Impact: High (I:H) – Arbitrary code execution.
• Availability Impact: High (A:H) – Potential for system compromise.

Threat Level: High. The vulnerability is remotely exploitable with low complexity, and while user interaction is required, it is easily achieved via social engineering. The lack of a patch increases the urgency for detection and mitigation.

Deep Dive & Mechanics

The vulnerability resides in the JP2 file parsing module of Sante DICOM Viewer Pro. JP2 (JPEG 2000 Part 2) files contain complex structures including image data, metadata, and color profiles. The specific flaw is an out-of-bounds write, meaning the software writes data beyond the allocated memory buffer when processing a specially crafted JP2 file.

Root Cause: The parser fails to validate the size or offset of data within the JP2 file before writing to a buffer. An attacker can manipulate fields such as the image dimensions, tile offsets, or component sizes to cause the parser to write past the end of an allocated object.

Exploitation Flow:

1. The attacker crafts a malicious JP2 file with oversized or malformed fields.
2. The victim opens the file in Sante DICOM Viewer Pro.
3. The parser reads the malicious data and performs a write operation beyond the buffer boundary.
4. This overwrites adjacent memory, potentially corrupting critical data structures or function pointers.
5. The attacker can then redirect execution flow to arbitrary code, achieving remote code execution.

Impact: Full compromise of the user's system, including access to DICOM images, patient data, and potential lateral movement within a healthcare network.

Vulnerable vs. Patched Code

Since no patch is available, a direct code comparison is not possible. However, based on the vulnerability type (out-of-bounds write), the vulnerable code likely resembles:

// Vulnerable pseudo-code
void parse_jp2_tile(unsigned char *data, unsigned int tile_size) {
    unsigned char *buffer = malloc(1024); // Fixed-size buffer
    memcpy(buffer, data, tile_size); // No bounds check
}

A patched version would include validation:

// Patched pseudo-code
void parse_jp2_tile(unsigned char *data, unsigned int tile_size) {
    unsigned char *buffer = malloc(1024);
    if (tile_size > 1024) {
        // Handle error or reallocate
        return;
    }
    memcpy(buffer, data, tile_size);
}

The fix would involve adding size checks before any write operation, ensuring that the data length does not exceed the allocated buffer size.

Exploitation & Lab Setup

Red Team (Offensive)

Lab Environment:

• Target: Windows 10/11 with Sante DICOM Viewer Pro (vulnerable version).
• Attacker: Kali Linux with Python and Metasploit.

Exploitation Steps:

1. Craft Malicious JP2 File: Use a fuzzer or manual manipulation to create a JP2 file with oversized tile data. For example, modify the tile width/height fields to cause a buffer overflow.
2. Deliver Payload: Host the file on a web server or send via email.
3. Trigger: Victim opens the file in Sante DICOM Viewer Pro.
4. Code Execution: The overflow overwrites a function pointer, redirecting execution to shellcode.

Example Python script to generate a malicious JP2 (conceptual):

import struct

def create_malicious_jp2():
    # Minimal JP2 header
    jp2 = b'\x00\x00\x00\x0c\x6a\x50\x20\x20\x0d\x0a\x87\x0a'
    # Image header box (oversized width)
    jp2 += struct.pack('>I', 0xFFFFFFFF)  # oversized width
    jp2 += b'A' * 4096  # padding to trigger overflow
    with open('malicious.jp2', 'wb') as f:
        f.write(jp2)

create_malicious_jp2()

Note: No public exploit code is available; this is a conceptual example.

Blue Team (Defensive)

Detection:

• Monitor for unusual JP2 file downloads or email attachments.
• Use endpoint detection and response (EDR) to detect memory corruption events.
• Implement application whitelisting to prevent unauthorized executables.

Mitigation:

• Disable JP2 file parsing if not needed.
• Use sandboxing or virtualization for DICOM viewer execution.
• Apply strict file validation before opening.

Indicators of Compromise (IOCs)

• File Hashes: (None available, but monitor for unknown JP2 files)
• Network Indicators: Connections to known malicious IPs after file opening.
• Process Behavior: Sante DICOM Viewer Pro crashing or exhibiting abnormal memory access.
• Registry/File System: Creation of suspicious files in temp directories.
• YARA Rule: (See Detection Engineering)

Detection Engineering

YARA Rule

rule CVE_2023_34297_JP2_Exploit {
    meta:
        description = "Detects malicious JP2 files targeting CVE-2023-34297"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2023-34297"
    strings:
        $jp2_magic = { 00 00 00 0C 6A 50 20 20 0D 0A 87 0A }
        $oversized = { FF FF FF FF }  // potential oversized field
    condition:
        $jp2_magic at 0 and #oversized > 0
}

Sigma Rule

title: CVE-2023-34297 Sante DICOM Viewer JP2 Exploit
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects process crashes or memory corruption events related to Sante DICOM Viewer Pro
author: Valters IT
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: 'SanteDicomViewer.exe'
        CommandLine|contains: '.jp2'
    condition: selection
falsepositives:
    - Legitimate JP2 file processing
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2023-34297 Sante DICOM Viewer JP2 Exploit"; flow:to_server,established; content:"|00 00 00 0C 6A 50 20 20 0D 0A 87 0A|"; depth:12; content:"|FF FF FF FF|"; within:100; classtype:attempted-user; sid:1000001; rev:1;)

Remediation & Mitigation

• Immediate: Disable JP2 file parsing in Sante DICOM Viewer Pro if possible. Use alternative DICOM viewers that are patched.
• Workaround: Implement file validation to reject JP2 files with anomalous headers or sizes.
• Patch: Monitor vendor for updates. No patch is currently available.
• Long-term: Apply principle of least privilege, use application sandboxing, and maintain robust backup and recovery procedures.

Valters IT Signature:
This report was generated by Valters IT DevSecOps AI. For questions, contact security@valters-it.com.