RHSA-2008:0680 - Security Advisory

Topic

An updated vsftpd package that fixes a security issue and various bugs is
now available.

This update has been rated as having moderate security impact by the Red
Hat Security Response Team.

Description

vsftpd (Very Secure File Transfer Protocol (FTP) daemon) is a secure FTP
server for Linux and Unix-like systems.

The version of vsftpd as shipped in Red Hat Enterprise Linux 4 when used in
combination with Pluggable Authentication Modules (PAM) had a memory leak
on an invalid authentication attempt. Since vsftpd prior to version 2.0.5
allows any number of invalid attempts on the same connection this memory
leak could lead to an eventual DoS. (CVE-2008-2375)

This update mitigates this security issue by including a backported patch
which terminates a session after a given number of failed log in attempts.
The default number of attempts is 3 and this can be configured using the
"max_login_fails" directive.

This package also addresses the following bugs:

• when uploading unique files, a bug in vsftpd caused the file to be saved

with a suffix '.1' even when no previous file with that name existed. This
issues is resolved in this package.

• when vsftpd was run through the init script, it was possible for the init

script to print an 'OK' message, even though the vsftpd may not have
started. The init script no longer produces a false verification with this
update.

• vsftpd only supported usernames with a maximum length of 32 characters.

The updated package now supports usernames up to 128 characters long.

• a system flaw meant vsftpd output could become dependent on the timing or

sequence of other events, even when the "lock_upload_files" option was set.
If a file, filename.ext, was being uploaded and a second transfer of the
file, filename.ext, was started before the first transfer was finished, the
resultant uploaded file was a corrupt concatenation of the latter upload
and the tail of the earlier upload. With this updated package, vsftpd
allows the earlier upload to complete before overwriting with the latter
upload, fixing the issue.

• the 'lock_upload_files' option was not documented in the manual page. A

new manual page describing this option is included in this package.

• vsftpd did not support usernames that started with an underscore or a

period character. These special characters are now allowed at the beginning
of a username.

• when storing a unique file, vsftpd could cause an error for some clients.

This is rectified in this package.

• vsftpd init script was found to not be Linux Standards Base compliant.

This update corrects their exit codes to conform to the standard.

All vsftpd users are advised to upgrade to this updated package, which
resolves these issues.

Solution

Before applying this update, make sure that all previously-released
errata relevant to your system have been applied.

This update is available via Red Hat Network. Details on how to use
the Red Hat Network to apply this update are available at
http://kbase.redhat.com/faq/FAQ_58_10188

Affected Products

• Red Hat Enterprise Linux Server 4 x86_64
• Red Hat Enterprise Linux Server 4 ia64
• Red Hat Enterprise Linux Server 4 i386
• Red Hat Enterprise Linux for IBM z Systems 4 s390x
• Red Hat Enterprise Linux for IBM z Systems 4 s390
• Red Hat Enterprise Linux for Power, big endian 4 ppc

Fixes

• BZ - 197141 - vsftpd 2.0.1 memory leak
• BZ - 206843 - vsftpd is checked wrongly in init script
• BZ - 236326 - maximum username length too short
• BZ - 240550 - vsftpd has a create/lock race condition which corrupts uploads
• BZ - 250727 - Uploaded file corrupted when two connections from same client uploading same file simultaneously
• BZ - 316381 - lock_upload_files not documented in vsftpd.conf man page
• BZ - 408431 - Memory leak in pattern matching function
• BZ - 431450 - Wrong init script
• BZ - 453376 - CVE-2008-2375 older vsftpd authentication memory leak

CVEs

• CVE-2008-2375

References

• http://www.redhat.com/security/updates/classification/#moderate