Samba 2.2.8 Available, Fixes Serious Security Vulnerability

 Subject:  [SECURITY] Samba 2.2.8 available for download From:     "Gerald (Jerry) Carter"  Date:     2003-03-15 14:13:20  -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1  This release provides an important security fix outlined in the  release notes that follow. This is the latest stable release of  Samba and the version that all production Samba servers should be  running for all current bug-fixes.  The source code can be downloaded from :      https://download.samba.org/pub/samba/  in the file samba-2.2.8.tar.gz or samba-2.2.8.tar.bz2.  The  uncompressed tarball has been signed using the Samba Distribution  Key (available in the same directory).  Binary packages will be released shortly for major platforms and can be found at      https://download.samba.org/pub/samba/Binary_Packages/  As always, all bugs are our responsibility.                             --Sincerely                            The Samba Team                  ****************************************                * IMPORTANT: Security bugfix for Samba *                ****************************************  Summary - -------  The SuSE security audit team, in particular Sebastian Krahmer , has found a flaw in the Samba main smbd code which could allow an external attacker to remotely and anonymously gain Super User (root) privileges on a server running a Samba server.  This flaw exists in previous versions of Samba from 2.0.x to 2.2.7a inclusive.  This is a serious problem and all sites should either upgrade to Samba 2.2.8 immediately or prohibit access to TCP ports 139 and 445. Advice created by Andrew Tridgell, the leader of the Samba  Team, on how to protect an unpatched Samba server is given at the end  of this section.  The SMB/CIFS protocol implemented by Samba is vulnerable to many attacks, even without specific security holes.  The TCP ports 139 and the new port 445 (used by Win2k and the Samba 3.0 alpha code in particular) should never be exposed to untrusted networks.  Description - -----------  A buffer overrun condition exists in the SMB/CIFS packet fragment re-assembly code in smbd which would allow an attacker to cause smbd to overwrite arbitrary areas of memory in its own process address space. This could allow a skilled attacker to inject binary specific exploit code into smbd.  This version of Samba adds explicit overrun and overflow checks on fragment re-assembly of SMB/CIFS packets to ensure that only valid re-assembly is performed by smbd.  In addition, the same checks have been added to the re-assembly functions in the client code, making it safe for use in other services.  Credit - ------  This security flaw was discovered and reported to the Samba Team by Sebastian Krahmer  of the SuSE Security Audit Team. The fix was prepared by Jeremy Allison and reviewed by engineers from the Samba Team, SuSE, HP, SGI, Apple, and the Linux vendor engineers on the Linux Vendor security mailing list.  The Samba Team would like to thank SuSE and Sebastian Krahmer for their excellent auditing work and for drawing attention to this flaw.  Patch Availability - -----------------  As this is a security issue, patches for this flaw specific to earlier versions of Samba will be posted on the samba-technical@samba.org mailing list as requested.   ************************************ Protecting an unpatched Samba server ************************************    Samba Team, March 2003    This is a note on how to provide your Samba server some   protection against the recently discovered remote security   hole if you are unable to upgrade to the fixed version   immediately. Even if you do upgrade you might like to think   about the suggestions in this note to provide you with   additional levels of protection.     Using host based protection   ---------------------------    In many installations of Samba the greatest threat comes for   outside your immediate network. By default Samba will accept   connections from any host, which means that if you run an   insecure version of Samba on a host that is directly   connected to the Internet you can be especially vulnerable.    One of the simplest fixes in this case is to use the 'hosts   allow' and 'hosts deny' options in the Samba smb.conf   configuration file to only allow access to your server from a   specific range of hosts. An example might be:       hosts allow = 127.0.0.1 192.168.2.0/24 192.168.3.0/24     hosts deny = 0.0.0.0/0    The above will only allow SMB connections from 'localhost'   (your own computer) and from the two private networks   192.168.2 and 192.168.3. All other connections will be   refused connections as soon as the client sends its first   packet. The refusal will be marked as a 'not listening on   called name' error.     Using interface protection   --------------------------    By default Samba will accept connections on any network   interface that it finds on your system. That means if you   have a ISDN line or a PPP connection to the Internet then   Samba will accept connections on those links. This may not be   what you want.    You can change this behavior using options like the   following:      interfaces = eth* lo     bind interfaces only = yes    that tells Samba to only listen for connections on interfaces   with a name starting with 'eth' such as eth0, eth1, plus on   the loopback interface called 'lo'. The name you will need to   use depends on what OS you are using. In the above I used the   common name for ethernet adapters on Linux.    If you use the above and someone tries to make a SMB   connection to your host over a PPP interface called 'ppp0',   they will get a TCP connection refused reply. In that   case no Samba code is run at all as the operating system has   been told not to pass connections from that interface to any   process.     Using a firewall   ----------------    Many people use a firewall to deny access to services that   they don't want exposed outside their network. This can be a   very good idea, although I would recommend using it in   conjunction with the above methods so that you are protected   even if your firewall is not active for some reason.    If you are setting up a firewall then you need to know what   TCP and UDP ports to allow and block. Samba uses the   following:      UDP/137    - used by nmbd     UDP/138    - used by nmbd     TCP/139    - used by smbd     TCP/445    - used by smbd    The last one is important as many older firewall setups may   not be aware of it, given that this port was only added to   the protocol in recent years.     Using a IPC$ share deny   -----------------------    If the above methods are not suitable, then you could also   place a more specific deny on the IPC$ share that is used in   the recently discovered security hole. This allows you to   offer access to other shares while denying access to IPC$   from potentially untrustworthy hosts.    To do that you could use:      [ipc$]         hosts allow = 192.168.115.0/24 127.0.0.1         hosts deny = 0.0.0.0/0    this would tell Samba that IPC$ connections are not allowed   from anywhere but the two listed places (localhost and a   local subnet). Connections to other shares would still be   allowed. As the IPC$ share is the only share that is always   accessible anonymously this provides some level of protection   against attackers that do not know a username/password for   your host.     If you use this method then clients will be given a 'access   denied' reply when they try to access the IPC$ share. That   means that those clients will not be able to browse shares,   and may also be unable to access some other resources.    I don't recommend this method unless you cannot use one of   the other methods listed above for some reason.     Upgrading Samba   ---------------    Of course the best solution is to upgrade Samba to a version   where the bug has been fixed. If you wish to also use one of   the additional measures above then that would certainly be a   good idea.    Please check regularly on https://www.samba.org/ for updates   and important announcements.               ****************************************             ****************************************  - -----------------------------------------------------------------  Changes since 2.2.7a - --------------------  New Parameters      * acl compatibility  Additional Changes:     See the cvs log for SAMBA_2_2 for more details  1)  smbumount lazy patch from Mandrake 2)  Check for too many processes *before* the fork. 3)  make sure we don't run over the end of 'name' in unix_convert() 4)  set umask to 0 before creating socket directory. 5)  Fix the LARGE_SMB_OFF_T problems and allow smbd to do the right     thing in interactive mode when a log file dir is also specified. 6)  Fix delete on close semantics to match W2K. 7)  Correctly return access denied on share mode deny when we can't     open the file. 8)  Always use safe_strcpy not pstrcpy for malloc()'d strings 9)  Fixes for HP-UX only having limited POSIX lock range 10) Added uid/gid caching code. Reduces load on winbindd. 11) Removed extra copy of server name in the printername field (it was     mangling the the name to be \\server\\\server\printer 12) Fix dumb perror used without errno being set. 13) Do retries correctly if the connection to the DC has failed. 14) Correctly check for inet_addr fail. 15) Ensure we use getgrnam() unless BROKEN_GETGRNAM is defined. 16) Fix for missing if (setting_acls) on default perms. 17) Fix to cache the sidtype 18) fix printer settings on Solaris (big-endian) print servers.     ASCII -> UNICODE conversion bug. 19) Small fix check correct error return. 20) Ensure space_avail is unsigned. 21) patch to check for a valid [f]chmod_acl function pointer     before calling it.  Fixes seg fault in audit VFS module 22) When checking is_locked() new WRITE locks conflict with existing     READ locks even if the context is the same. 23) Merge off-by-one crash fixes from HEAD 24) Move off-by-one buggy malloc()/safe_strcpy() combination to     strdup() instead. 25) Merge from HEAD. Use pstrcpy not safe_strcpy. 26) Fix to allow blocking lock notification to be done rapidly (no wait     for smb -> smb lock release). Adds new PENDING_LOCK type to lockdb     (does not interfere with existing locks). 27) Doxygen cleanups for code documentation 28) limit the unix domain sockets used by winbindd  by adding a     "last_access" field to winbindd connections, and will close     the oldest idle connection once the number of open connections goes     over WINBINDD_MAX_SIMULTANEOUS_CLIENTS (defined in local.h as 200     currently) 29) Fix a couple of string handling errors in smbd/dir.c that would     cause smbd to crash 30) Fix seg fault in smbpasswd when specifying the new password     as a command line argument 31) Correct 64-but file sizes issues with smbtar and smbclient 32) Add batch mode option to pdbedit 33) Add protection in nmbd against malformed reply packets 34) Fix bug with sendfile profiling support in smbstatus output 35) Correct bug in "hide unreadable" smb.conf parameter that     resulted in incorrect directory listings 36) Fix bug in group enumeration in winbindd 37) Correct build issues with libsmbclient on Solaris 38) Fix memory leak and bad pointer dereference in password     changing code in smbd 39) Fix for changing attributes on a file truncate 40) Ensure smbd process count never gets to -1 if limiting number     of processes 41) Ensure we return disk full by default on short writes 42) Don't delete jobs submitted after the lpq time 43) Fix reference count bug where smbds would not terminate     with no open resources 44) Performance fix when using quota support on HP-UX 45) Fixes for --with-ldapsam     * Default to port 389 when "ldap ssl != on"     * add support for rebinding to the master directory server       for password changes when "ldap server" points to a read-only       slave 46) Add -W and -X command line flags to smbpasswd for extracting and     setting the machine/domain SID in secrets.tdb.  See the     smbpasswd(8) man page for details. 47) Added (c) Luke Howard to winbind_nss_solaris.c for coded     obtained from PADL's nss_ldap library. 48) Fix bug in samr_dispinfo query in winbindd 49) Fix segfault in NTLMSSP password changing code for     guest connections 50) Correct pstring/fstring mismatches 51) Send level II oplock break requests synchronously to prevent     condition where one smbd would continually lock a share entry     in locking.tdb 52) Miscellaneous cleanups for tdb error conditions and appending     data in a record 53) Implement correct open file truncate semantics with DOS     attributes 54) Enforce wide links = no on files as well as directories 55) Include shared library checks for Stratus VOS 56) Include support for CUPS printer classes and logging the remote     client name 57) Include  "WinXP" (Windows XP) and "Win2K3" (Windows .NET) values     for %a 58) Increase the max PDU size to deal with some troublesome printer     drivers and Windows NT 4.0 clients 59) increment the process counter immediately after the fork     (not just when we receive the first smb packet) 60) Ensure rename sets errno correctly 61) Unify ACL code (back-port from 3.0) 62) Fix some further issues around off_t and large offsets  -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.0 (GNU/Linux) Comment: For info see   iD8DBQE+czUBIR7qMdg1EfYRAtw3AJ0aOssqot9nSJPrtdciVxb/Q2DxTQCgtHEA VK0cv2KDuqWWoLesbW1tQpM= =GIxq -----END PGP SIGNATURE-----