Horizon Alert
Summary of the vulnerability and why it matters
A configuration flaw within Samba file servers and domain controllers could allow remote attackers to execute commands. This vulnerability arises when the "check password script" feature is used with a specific substitution character, leading to improper handling of client-supplied usernames. If exploited, this could result in unauthorized command execution on the affected system.
- Vulnerable: Samba "check password script" feature
- Flaw: Username passed without proper shell meta-character escaping
- Impact: Remote command execution on systems
Attack Path
How an attacker could exploit the issue
A misconfiguration in Samba file servers and classic domain controllers can allow remote attackers to execute commands. This occurs when the "check password script" feature is used with a specific substitution character, leading to improper handling of client-provided usernames. The attack can result in remote command execution on the affected system, particularly when the `samba-dcerpcd` service is running as a system service.
- Exposed Samba servers with specific script misconfiguration.
- Attacker sends crafted username to trigger script.
- Attacker gains remote command execution.
Live Threat
Current exploitation, exposure, and threat context
A vulnerability in Samba's "check password script" feature could allow attackers to execute commands remotely on affected systems. This impacts organizations using specific, non-standard Samba configurations where this feature is enabled and susceptible to shell meta-character injection. The potential for remote command execution presents a significant business risk, demanding prompt attention.
- Likely attacker skill: Advanced
- Required access: Network access, specific misconfiguration
- Business risk: High, treat as urgent
Priority actions
Operational Fix
Recommended remediation, mitigation, and detection steps
An organization should address a critical flaw in Samba that could allow remote command execution. This vulnerability arises from a misconfiguration in specific Samba file servers and domain controllers using the "check password script" feature with a particular substitution character. Exploitation requires a non-standard setup where this script is configured improperly and the samba-dcerpcd service runs as a system service. The risk primarily impacts organizations with these specific, less common configurations.
- Identify Samba servers using the "check password script" with the affected substitution character.
- Isolate or restrict network access to potentially misconfigured Samba services.
- Apply vendor updates and validate the fix.
