Samba has disclosed a extreme distant code execution (RCE) flaw that would permit attackers to hijack Energetic Listing area controllers.
Tracked as CVE-2025-10230, the vulnerability stems from improper validation within the Home windows Web Identify Service (WINS) hook mechanism, incomes an ideal CVSS 3.1 rating of 10.0 for its ease of exploitation and devastating potential influence.
Samba, the open-source implementation of the SMB/CIFS networking protocol extensively utilized in Linux and Unix environments to imitate Home windows file sharing and authentication, has lengthy been a cornerstone for cross-platform enterprise networks.
Nonetheless, this flaw exposes organizations counting on it as an Energetic Listing Area Controller (AD DC) to unauthenticated assaults.
Found by safety researcher Igor Morgenstern of Aisle Analysis, the difficulty impacts all Samba variations since 4.0 when particular configurations are enabled, specifically, WINS help and a customized ‘wins hook’ script within the smb.conf file.
Samba RCE Vulnerability
WINS, a deprecated Microsoft protocol from the pre-DNS period, resolves NetBIOS names in legacy Home windows networks.
By default, WINS help is disabled in Samba, however when activated on an AD DC alongside the ‘wins hook’ parameter, which triggers an exterior script on identify modifications, the system turns into a sitting duck.
Attackers can ship crafted WINS identify registration requests containing shell metacharacters inside the 15-character NetBIOS restrict.
These inject arbitrary instructions into the hook script, executed by way of a shell with none authentication or consumer interplay required.
The vulnerability’s scope is slender however perilous: it solely impacts Samba in AD DC mode (roles like ‘area controller’ or ‘energetic listing area controller’).
Standalone or member servers, which use a distinct WINS implementation, stay unaffected. In apply, this might let distant risk actors on the community pivot to full system compromise, exfiltrating delicate knowledge, deploying ransomware, or escalating privileges in hybrid Home windows-Linux setups frequent in enterprises.
Mitigations
Samba maintainers acted swiftly, releasing patches to their safety portal and issuing up to date variations: 4.23.2, 4.22.5, and 4.21.9.
Directors ought to prioritize upgrades, particularly in environments with legacy WINS dependencies.
As a workaround, disable the ‘wins hook’ parameter fully or set ‘wins help = no’ in smb.conf Samba’s default configuration already avoids this dangerous combo, making most setups protected out of the field.
Consultants urge a broader overview: WINS is out of date, and its use on fashionable area controllers is uncommon and inadvisable. Even post-patch, admins would possibly disable hooks altogether, as future Samba releases may drop help.
With assault surfaces increasing in hybrid clouds, this incident underscores the necessity to audit and part out antiquated protocols earlier than they grow to be entry factors for nation-state actors or cybercriminals.
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