Description
A flaw was found in Samba, in the front-end WINS hook handling: NetBIOS names from registration packets are passed to a shell without proper validation or escaping. Unsanitized NetBIOS name data from WINS registration packets are inserted into a shell command and executed by the Samba Active Directory Domain Controller’s wins hook, allowing an unauthenticated network attacker to achieve remote command execution as the Samba process.
EPSS Score:
0%
Comprehensive Technical Analysis of EUVD-2025-38301
1. Vulnerability Assessment and Severity Evaluation
The vulnerability described in EUVD-2025-38301 pertains to a critical flaw in Samba, specifically in the handling of WINS (Windows Internet Name Service) registration packets. The issue arises from the lack of proper validation or escaping of NetBIOS names, which are passed to a shell command and executed by the Samba Active Directory Domain Controller’s WINS hook. This allows an unauthenticated network attacker to achieve remote command execution as the Samba process.
Severity Evaluation:
- CVSS Base Score: 10.0 (Critical)
- CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
The CVSS score of 10.0 indicates the highest level of severity. The vulnerability can be exploited over the network (AV:N) with low complexity (AC:L), requires no privileges (PR:N), and no user interaction (UI:N). The impact is severe, affecting confidentiality, integrity, and availability (C:H/I:H/A:H).
2. Potential Attack Vectors and Exploitation Methods
Attack Vectors:
- Unauthenticated Network Attack: An attacker can send specially crafted WINS registration packets to the vulnerable Samba server.
- Remote Command Execution: The attacker can inject malicious commands into the NetBIOS names, which are then executed by the Samba process.
Exploitation Methods:
- Crafting Malicious Packets: The attacker can use tools to craft WINS registration packets with malicious NetBIOS names.
- Command Injection: The malicious NetBIOS names can include shell commands that the Samba process will execute, leading to remote code execution.
3. Affected Systems and Software Versions
Affected Systems:
- Samba servers configured as Active Directory Domain Controllers with the WINS hook enabled.
Software Versions:
- Specific versions of Samba are affected. Refer to the Samba security history and Red Hat advisories for exact version details.
4. Recommended Mitigation Strategies
Immediate Actions:
- Patching: Apply the latest security patches provided by Samba and Red Hat.
- Disable WINS Hook: If not required, disable the WINS hook to prevent exploitation.
- Network Segmentation: Isolate Samba servers from untrusted networks to limit exposure.
Long-Term Strategies:
- Regular Updates: Ensure that all software, including Samba, is regularly updated and patched.
- Monitoring: Implement monitoring and logging to detect and respond to suspicious activities.
- Access Controls: Enforce strict access controls and network policies to limit unauthorized access.
5. Impact on European Cybersecurity Landscape
The vulnerability poses a significant risk to organizations using Samba as an Active Directory Domain Controller, particularly those in Europe. Given the critical nature of the flaw, it could lead to widespread compromises if not addressed promptly. The European Union's cybersecurity frameworks, such as the NIS Directive and GDPR, emphasize the importance of timely patching and incident response, making this vulnerability a high priority for compliance and risk management.
6. Technical Details for Security Professionals
Vulnerability Details:
- Root Cause: Improper validation and escaping of NetBIOS names in WINS registration packets.
- Exploitation: The unsanitized data is passed to a shell command, allowing command injection.
Detection and Response:
- Intrusion Detection Systems (IDS): Configure IDS to detect anomalous WINS traffic and suspicious shell command executions.
- Log Analysis: Review Samba logs for unusual activities, particularly around WINS hook operations.
- Incident Response: Develop and implement an incident response plan specific to this vulnerability, including containment, eradication, and recovery steps.
References:
By addressing this vulnerability promptly and comprehensively, organizations can mitigate the risk of remote command execution and maintain the integrity and security of their Samba deployments.