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T-024: Vulnerability in Server Message Block (SMB)
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NSMB.CONF(5) BSD File Formats Manual NSMB.CONF(5) NAME
nsmb.conf -- configuration file for SMB requests DESCRIPTION
The nsmb.conf file contains information about the computers and shares or mount points for the SMB network protocol. The configuration hierarchy is made up of several sections, each section containing a few or several lines of parameters and their assigned values. Each of these sections must begin with a section name enclosed within square brackets, similar to: [section_name] The end of each section is marked by either the start of a new section, or by the abrupt ending of the file, commonly referred to as the EOF. Each section may contain zero or more parameters such as: [section_name] key=value where key represents a parameter name, and value would be the parameter's assigned value. The SMB library uses the following information for section names: A) [default] B) [SERVER] C) [SERVER:SHARE] Possible keywords may include: Keyword Section Default Comment A B C Values addr - + - DNS name or IP address of server nbtimeout + + - 1s Timeout for resolving a NetBIOS name minauth + + - NTLM Minimum authentication level allowed port445 + + - normal How to use SMB TCP/UDP ports streams + + + yes Use NTFS Streams if server supported soft + + + Make the mount soft notify_off + + + no Turn off using notifications kloglevel + - - 0 Turn on smb kernel logging smb_neg + - - normal How to negotiate SMB 2.x signing_required + - - false Turn off smb client signing The minimum authentication level can be one of: kerberos Kerberos - NTLMv2, NTLM, LM, and plain-text password authentication are not attempted. ntlmv2 NTLMv2 - Kerberos authentication is attempted if a Kerberos token can be obtained, otherwise NTLMv2 authentication is attempted; if the server doesn't support encrypted passwords, the authentication fails. ntlm NTLM - Kerberos authentication is attempted if a Kerberos token can be obtained, otherwise NTLMv2 authentication is attempted and, if that fails, NTLMv1 authentication is attempted, with zeroes in the LM hash; if the server doesn't support encrypted passwords, the authentication fails. lm LM - Kerberos authentication is attempted if a Kerberos token can be obtained, otherwise NTLMv2 authentication is attempted and, if that fails, NTLMv1 authentication is attempted, including the LM hash; if the server doesn't support encrypted passwords, the authentication fails. none none - The same as lm except that, if the server doesn't support encrypted passwords, plain-text passwords are used. Required for servers that don't support extended security. (Note: "NetBIOS" as used below means "NetBIOS over TCP/IP.") "How to use SMB TCP/UDP ports" can be one of: normal Attempt to connect via port 445. If that is unsuccessful, try to connect via NetBIOS. netbios_only Do not attempt to connect via port 445. no_netbios Attempt to connect via port 445. If that is unsuccessful, do not try to connect via NetBIOS. "How to negotiate SMB 2.x" can be one of: normal Negotiate with SMB 1.x and attempt to negotiate to SMB 2.x. smb1_only Negotiate with only SMB 1.x. smb2_only Negotiate with only SMB 2.x. This also will set no_netbios. FILES
/etc/nsmb.conf The global configuration file. ~/Library/Preferences/nsmb.conf The user's configuration file, conflicts will be overwritten by the global file. EXAMPLES
What follows is a sample configuration file which may, or may not match your environment: # Configuration file for example.com [default] minauth=ntlmv2 streams=yes soft=yes notify_off=yes [WINXP] addr=windowsXP.apple.com All lines which begin with the '#' character are comments and will not be parsed. The ``default'' section specifies that only Kerberos and NTLMv2 authentication should be attempted; NTLM authentication should not be attempted if NTLMv2 authentication fails, and plain-text authen- tication should not be attempted if the server doesn't support encrypted passwords. SEE ALSO
smbutil(1), mount_smbfs(8) AUTHORS
This manual page was originally written by Sergey Osokin <osa@FreeBSD.org> and Tom Rhodes <trhodes@FreeBSD.org>. BSD
June 30, 2003 BSD
