Linux Security
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Linux Security

Debian: 'samba' remote file append/creation vulnerability

Date 23 Jun 2001
Posted By LinuxSecurity Advisories
Samba can be tricked into appending any data he wants to all files on the filesystem which samba can write to under certain circumstances.

Debian Security Advisory DSA-065-1                   This email address is being protected from spambots. You need JavaScript enabled to view it.                         Wichert Akkerman
June 23, 2001

Package        : samba
Problem type   : remote file append/creation
Debian-specific: no

Michal Zalewski discovered that samba does not properly validate
NetBIOS names from remote machines.

By itself that is not a problem, except if Samba is configure to
write log-files to a file that includes the NetBIOS name of the
remote side by using the `%m' macro in the `log file' command. In
that case an attacker could use a NetBIOS name like '../tmp/evil'.
If the log-file was set to "/var/log/samba/%s" samba would them
write to /var/tmp/evil.

Since the NetBIOS name is limited to 15 characters and the `log
file' command could have an extension to the filename the results
of this are limited. However if the attacker is also able to create
symbolic links on the samba server he could trick samba into
appending any data he wants to all files on the filesystem which
samba can write to.

The Debian GNU/Linux packaged version of samba has a safe
configuration and is not vulnerable.

As temporary workaround for systems that are vulnerable change all
occurrences of the `%m' macro in smb.conf to `%l' and restart samba.

This has been fixed in version 2.0.7-3.4, and we recommend that up
upgrade your samba package immediately.

wget url
        will fetch the file for you
dpkg -i file.deb
        will install the referenced file.

Debian GNU/Linux 2.2 alias potato

  Potato was released for alpha, arm, i386, m68k, powerpc and sparc.

  Source archives:
      MD5 checksum: 5611001a7ed3b80214709ee1f5b433cf
      MD5 checksum: 1899ddf270b1c7422297b5725aae1cac
      MD5 checksum: b5e61ea655d476072fd0365785fea2d0

  Architecture independent archives:
      MD5 checksum: 5e9e67fd0b0647945106ec4af85aec6e

  Alpha architecture:
      MD5 checksum: f978de80e3dcfdd5a08c623b365c1a88
      MD5 checksum: 139272e3c7f6fc6643b303db996736a3
      MD5 checksum: 106f37c91188799ba73f5821582cce82
      MD5 checksum: 5eba972f8f5ec99b9ac31281ff93b862
      MD5 checksum: 1fddc7995e9068fba6f509222c386b36

  ARM architecture:
      MD5 checksum: 4cebf21d3d52f80250688b79d078cffe
      MD5 checksum: 5e98051170c741a8d982cd4eedd1ee2d
      MD5 checksum: 8968608080bf324dbab1dbca607066cd
      MD5 checksum: f57810ea2d6c7686d090ed84ccfb168f
      MD5 checksum: a14b4f352fdca1986d5142c8584c3d15

  Intel IA-32 architecture:
      MD5 checksum: 68a2b37078da7ae8bfe494ba4406f9b7
      MD5 checksum: 9e7d7b60348a4aa2d3f401e30a7078c9
      MD5 checksum: fff14586173645b3ee81129f071ea462
      MD5 checksum: f07facfb2938d08f76f4aef1a4ccba54
      MD5 checksum: aa9665611e949b70c5157c51329f765e

  Motorola 680x0 architecture:
      MD5 checksum: db9593e35e444ede9ebe7c8583813166
      MD5 checksum: d7df68eef17e69a52d9e6d43532f4fca
      MD5 checksum: 99e120404688b3834467a5d9654b5066
      MD5 checksum: 414a4563a94386bdc7064fa3fa655af5
      MD5 checksum: 1886e731d2aa8de279cdbd40c23d08cd

  PowerPC architecture:
      MD5 checksum: 46d0b904f84472dd446d6bc6598a7611
      MD5 checksum: 79ffd3bc7f11c7a5010a36a390e254ae
      MD5 checksum: 678b59800ac66aab2744a5b4a1067494
      MD5 checksum: 451edca1851b05a743f4c371a1b4a428
      MD5 checksum: 8bf7246835c70edff54c2c106c06d41f

  Sun Sparc architecture:
      MD5 checksum: c3d1ece362929b928271e1549d618583
      MD5 checksum: cc11c140c1d05fb59c9cf68c3b19870c
      MD5 checksum: a31eacb646466c408183a72b030ebfa6
      MD5 checksum: f411a3651f63e466066d4f85bfb3dc6e
      MD5 checksum: 26a982c6b747338883a1be57e6fefc2d

  These packages will be moved into the stable distribution on its next

For not yet released architectures please refer to the appropriate
directory$arch/ .

apt-get: deb stable/updates main
dpkg-ftp: dists/stable/updates/main
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