CVE-2025-57776

Executive Summary

CVE-2025-57776 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 allows an attacker to write data to an invalid memory address. Successful exploitation requires user interaction (opening a malicious .dsb file) and can lead to arbitrary code execution in the context of the DASYLab process. With a CVSS score of 7.8, this vulnerability poses a significant risk to industrial control, data acquisition, and laboratory environments where DASYLab is deployed. No public exploit code or patch is currently available, making detection and user awareness the primary defense.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby ecosystems. It is a standalone desktop application (DASYLab) used in engineering and scientific data acquisition.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
• Base Score: 7.8 (High)
• Attack Vector: Local (AV:L) – requires the attacker to deliver a malicious file to the target system.
• Attack Complexity: Low (AC:L) – no special conditions beyond file opening.
• Privileges Required: None (PR:N) – no authentication needed.
• User Interaction: Required (UI:R) – victim must open the crafted DSB file.
• Scope: Unchanged (S:U) – exploitation stays within the vulnerable component.
• Confidentiality Impact: High (C:H) – arbitrary code execution can read sensitive data.
• Integrity Impact: High (I:H) – code execution can modify or destroy data.
• Availability Impact: High (A:H) – code execution can crash or take over the system.

Threat Level: High. The lack of a patch and the potential for code execution in critical industrial environments elevates the risk.

Deep Dive & Mechanics

The vulnerability is an out-of-bounds write (CWE-787) in the DSB file parser of DASYLab. DSB files are binary data storage files used by DASYLab to store measurement configurations, signal processing setups, and recorded data. The parser fails to validate the size of a data block or array index before writing to a buffer, allowing an attacker to craft a DSB file with a maliciously large offset or size value. When the parser processes this field, it writes data beyond the allocated buffer boundary, corrupting adjacent memory.

Root Cause: Improper bounds checking in the parsing logic. The code likely uses a fixed-size buffer but trusts the file-supplied size without verifying it against the buffer capacity.

Exploitation Path:

1. Attacker crafts a DSB file with a manipulated header or data block containing an oversized length field.
2. Victim opens the file in DASYLab (e.g., via double-click or File > Open).
3. The parser reads the malicious length, allocates or uses a buffer, then writes data beyond its bounds.
4. The out-of-bounds write overwrites critical data structures (e.g., function pointers, return addresses) leading to arbitrary code execution.

Impact: Full compromise of the DASYLab process, potentially allowing the attacker to execute shellcode, install malware, or pivot to other systems on the network.

Vulnerable vs. Patched Code

Since no patch is available, a hypothetical fix is described.

Vulnerable Code (C-like pseudocode):

void parse_dsb_block(FILE *file) {
    char buffer[256];
    uint32_t data_size;
    fread(&data_size, sizeof(data_size), 1, file);
    // No bounds check
    fread(buffer, 1, data_size, file);
}

Patched Code (hypothetical):

void parse_dsb_block(FILE *file) {
    char buffer[256];
    uint32_t data_size;
    fread(&data_size, sizeof(data_size), 1, file);
    if (data_size > sizeof(buffer)) {
        // Handle error, reject file
        return;
    }
    fread(buffer, 1, data_size, file);
}

Exploitation & Lab Setup

Red Team

Objective: Achieve arbitrary code execution via a crafted DSB file.

Prerequisites:

• DASYLab installed (any version).
• Ability to deliver the malicious DSB file to the target (e.g., email, USB, network share).

Steps:

1. Analyze DSB Format: Reverse engineer the DSB file structure to identify the vulnerable field (e.g., a block size or array length).
2. Craft Payload: Create a DSB file where the vulnerable field is set to a value larger than the buffer size. Include shellcode or ROP chain in the data that will overwrite a return address or function pointer.
3. Deliver File: Send the file to the victim via phishing email or social engineering.
4. Trigger: Victim opens the file in DASYLab.
5. Execute: The out-of-bounds write corrupts memory, and upon function return or indirect call, the attacker's code executes.

Example Exploit Skeleton (Python):

import struct

def craft_malicious_dsb(output_path):
    # Hypothetical DSB structure
    header = b'\x00' * 16  # Placeholder header
    # Vulnerable block: size field = 0xFFFFFFFF (max uint32)
    size_field = struct.pack('<I', 0xFFFFFFFF)
    # Payload: shellcode or ROP chain
    payload = b'\x90' * 1000  # NOP sled + shellcode
    malicious_data = header + size_field + payload
    with open(output_path, 'wb') as f:
        f.write(malicious_data)

craft_malicious_dsb('exploit.dsb')

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

Blue Team

Objective: Detect and prevent exploitation of CVE-2025-57776.

Detection:

• Monitor for unusual DSB file sizes or files with suspiciously large block headers.
• Use endpoint detection and response (EDR) to alert on DASYLab process crashes or memory corruption events.
• Deploy application whitelisting to prevent unauthorized executables spawned by DASYLab.

Prevention:

• Restrict execution of DASYLab to trusted users only.
• Use sandboxing or virtualization for opening DSB files from untrusted sources.
• Implement file reputation scanning for DSB files at the email gateway or endpoint.

Hunting:

• Search for DASYLab processes that exhibit abnormal memory allocation or access violations.
• Look for child processes (e.g., cmd.exe, powershell.exe) spawned by DASYLab.

Indicators of Compromise (IOCs)

• File Hashes (example): SHA256 of a malicious DSB file (none public).
• Process Names: DASYLab.exe, DASYLab64.exe
• Network Connections: Outbound connections from DASYLab to unknown IPs (post-exploitation C2).
• Registry Keys: Modifications to HKEY_CURRENT_USER\Software\Digilent\DASYLab (if persistence is attempted).
• File Artifacts: .dsb files with anomalous sizes (e.g., > 10 MB) or containing executable code in data blocks.
• Memory Artifacts: Heap spray patterns or shellcode in DASYLab process memory.

Detection Engineering

YARA Rule

rule CVE_2025_57776_DSB_Malicious {
    meta:
        description = "Detects potentially malicious DSB files exploiting CVE-2025-57776"
        author = "Valters IT"
        date = "2025-04-10"
        hash = "unknown"
    strings:
        $dsb_magic = { 44 53 42 } // "DSB" magic bytes (hypothetical)
        $large_size = { FF FF FF 7F } // 0x7FFFFFFF or larger size field
    condition:
        $dsb_magic at 0 and $large_size
}

Sigma Rule

title: CVE-2025-57776 DASYLab DSB File Exploitation Attempt
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects potential exploitation of CVE-2025-57776 via DASYLab process crash or abnormal memory access
author: Valters IT
date: 2025-04-10
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\DASYLab.exe'
        CommandLine|contains: '.dsb'
    condition: selection
falsepositives:
    - Legitimate DSB file openings
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-57776 DASYLab Potential C2 Beacon"; flow:to_server,established; content:"|90 90 90 90|"; depth:100; classtype:attempted-user; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable DSB File Association: Prevent automatic opening of .dsb files by removing the file association in Windows.
2. User Awareness: Train users not to open DSB files from untrusted sources.
3. Application Control: Use AppLocker or similar to restrict DASYLab execution to approved users.

Long-Term:

• Monitor vendor (Digilent) for an official patch or update.
• Consider migrating to alternative data acquisition software if no patch is released.
• Implement strict file validation for DSB files at the perimeter (e.g., email attachment scanning).

Workaround: If DASYLab is essential, run it in a sandboxed environment (e.g., Windows Sandbox, Firejail) to contain potential exploits.

Valters IT