CVE-2025-13776: Finka-Faktura Information Disclosure Flaw

CVE-2025-13776 Overview

Multiple Finka programs use hard-coded Firebird database credentials that are shared across all instances of the software. This hardcoded credentials vulnerability (CWE-798) allows a malicious attacker on the local network who knows the default credentials to read and modify database content, potentially compromising sensitive business data stored by these accounting and business management applications.

Critical Impact

Attackers with local network access can leverage hardcoded database credentials to gain unauthorized read and write access to sensitive financial and business data across all affected Finka application deployments.

Affected Products

• Finka-FK (versions prior to 18.5)
• Finka-KPR (versions prior to 16.6)
• Finka-Płace (versions prior to 13.4)
• Finka-Faktura (versions prior to 18.3)
• Finka-Magazyn (versions prior to 8.3)
• Finka-STW (versions prior to 12.3)

Discovery Timeline

• 2026-02-24 - CVE-2025-13776 published to NVD
• 2026-02-26 - Last updated in NVD database

Technical Details for CVE-2025-13776

Vulnerability Analysis

This vulnerability stems from the use of hardcoded credentials within multiple Finka business applications that connect to a Firebird database backend. The credentials are embedded directly in the application code and are identical across all deployed instances of the affected software. This design flaw means that any attacker who discovers these credentials—whether through reverse engineering, documentation leaks, or other means—can potentially access any Finka deployment on an accessible network segment.

The adjacent network attack vector indicates that exploitation requires the attacker to be on the same network segment as the target system. Once network adjacency is achieved, the attacker can connect directly to the Firebird database service using the known hardcoded credentials, bypassing any application-level authentication mechanisms.

Root Cause

The root cause of CVE-2025-13776 is the insecure practice of embedding static database credentials directly within the application code (CWE-798: Use of Hard-coded Credentials). Rather than implementing proper credential management—such as per-installation unique credentials, secure credential storage, or certificate-based authentication—the developers chose to use a single set of credentials shared across all installations. This approach creates a systemic vulnerability where the compromise of credentials from any single installation affects all deployments.

Attack Vector

The attack requires adjacent network access (AV:A), meaning the attacker must be positioned on the same local network segment as the target Finka installation. The attack complexity is low, requiring no authentication and no user interaction. Once an attacker has network access and knowledge of the hardcoded credentials, they can:

1. Scan the local network for Firebird database services (typically on port 3050)
2. Connect to discovered database instances using the hardcoded credentials
3. Read sensitive business data including financial records, invoices, and employee payroll information
4. Modify database content, potentially altering financial records or injecting malicious data

The vulnerability allows for high confidentiality and integrity impact, enabling both data theft and data manipulation. For additional technical details, refer to the CERT Poland CVE-2025-13776 Advisory.

Detection Methods for CVE-2025-13776

Indicators of Compromise

• Unexpected connections to Firebird database service (default port 3050) from unauthorized network hosts
• Authentication attempts to the Firebird database from IP addresses outside normal application server range
• Database query patterns inconsistent with normal application behavior
• Unauthorized read operations on sensitive tables containing financial or employee data

Detection Strategies

• Monitor network traffic for connections to Firebird database port 3050 from hosts other than authorized application servers
• Implement database activity monitoring to detect queries executed outside of normal application context
• Review Firebird database logs for authentication events from unexpected source addresses
• Deploy network segmentation monitoring to detect lateral movement attempts toward database servers

Monitoring Recommendations

• Enable and centralize Firebird database authentication and query logging
• Configure alerts for database connections from unauthorized IP ranges
• Implement baseline analysis of normal database query patterns to detect anomalies
• Monitor for scanning activity targeting Firebird service ports across the network segment

How to Mitigate CVE-2025-13776

Immediate Actions Required

• Update all Finka applications to the patched versions: Finka-FK 18.5, Finka-KPR 16.6, Finka-Płace 13.4, Finka-Faktura 18.3, Finka-Magazyn 8.3, Finka-STW 12.3
• Isolate Firebird database servers on dedicated network segments with strict access controls
• Implement firewall rules to restrict database access to only authorized application servers
• Audit database logs for any evidence of unauthorized access prior to patching

Patch Information

Finka has released updated versions for all affected products that address the hardcoded credentials vulnerability. Organizations should upgrade to the following minimum versions:

For more information about Finka products, visit the Finka official website.

Workarounds

• Implement strict network segmentation to isolate Firebird database servers from general network access
• Configure host-based firewalls on database servers to accept connections only from authorized application servers
• Deploy network access control (NAC) solutions to limit network adjacency attack opportunities
• Consider implementing additional database access controls through Firebird's built-in security features until patching is complete

# Example firewall rule to restrict Firebird access (Linux iptables)
# Allow only authorized application server (192.168.1.10) to connect
iptables -A INPUT -p tcp --dport 3050 -s 192.168.1.10 -j ACCEPT
iptables -A INPUT -p tcp --dport 3050 -j DROP