Security Advisory: REMOTE ROOT VULNERABILITY IN GSSFTP DAEMON

[tlyu () MIT EDU (Tom Yu)]

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              REMOTE ROOT VULNERABILITY IN GSSFTP DAEMON

2000-06-14

SUMMARY:

A remote user may execute certain FTP commands without authorization.

IMPACT:

A remote user may perform denial of service attacks.

An attacker with access to a local account may gain unauthorized root
access.

VULNERABLE DISTRIBUTIONS:

Source distributions which may contain vulnerable code include:

        MIT Kerberos 5 releases krb5-1.1 and krb5-1.1.1

The beta releases krb5-1.1.2-beta1 and krb5-1.2-beta2 are also
vulnerable.

NON-VULNERABLE DISTRIBUTIONS:

        MIT Kerberos 5 releases krb5-1.0.x

FIXES:

If you are running a vulnerable FTP daemon, disable it immediately,
usually by commenting it out of your inetd.conf and sending a SIGHUP
to the inetd process.

To correct the bug, apply the following patch, rebuild, and reinstall
ftpd on the affected machines.

The upcoming krb5-1.2 release will correct this problem.  There will
be a krb5-1.2-beta3 release later this week that will correct this
problem.

PATCHES:

These patches will apply against krb5-1.1.1, krb5-1.1.2-beta1, and
krb5-1.2-beta2.  They will be made available on the web site at:

        http://web.mit.edu/kerberos/www/advisories/ftpd_111_patch.txt

The MIT Kerberos security advisories page is at:

        http://web.mit.edu/kerberos/www/advisories/index.html

Patches for other security problems as well as archives of security
advisory postings are located on that page.

Index: ftpcmd.y
===================================================================
RCS file: /cvs/krbdev/krb5/src/appl/gssftp/ftpd/ftpcmd.y,v
retrieving revision 1.14
diff -c -r1.14 ftpcmd.y
*** ftpcmd.y    1999/03/24 22:14:02     1.14
- --- ftpcmd.y  2000/06/14 17:35:19
***************
*** 865,871 ****
                          $$ = 0;
                  }
                  else
!                       $$ = 1;
          }
          ;
  %%
- --- 865,871 ----
                          $$ = 0;
                  }
                  else
!                       $$ = $1;
          }
          ;
  %%

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