Red Hat: 'ntpd' buffer overflow
Posted by LinuxSecurity.com Team   
RedHat Linux The Network Time Daemon (xntpd on Red Hat Linux 6.2 and earlier, ntpd on Red Hat Linux 7.0) does not properly check the size of a buffer used to hold incoming data from the network.

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                   Red Hat, Inc. Red Hat Security Advisory

Synopsis:          Network Time Daemon (ntpd) has potential remote root exploit
Advisory ID:       RHSA-2001:045-05
Issue date:        2001-04-05
Updated on:        2001-04-08
Product:           Red Hat Linux
Keywords:          ntpd exploit buffer overflow
Cross references:  
Obsoletes:         
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1. Topic:

The Network Time Daemon (ntpd) supplied with all releases of Red Hat 
Linux is vulnerable to a buffer overflow, allowing a remote attacker to 
potentially gain root level access to a machine.  All users of ntpd are 
strongly encouraged to upgrade.

2. Relevant releases/architectures:

Red Hat Linux 5.2 - alpha, i386, sparc

Red Hat Linux 6.2 - alpha, i386, sparc

Red Hat Linux 7.0 - alpha, i386

3. Problem description:

The Network Time Daemon (xntpd on Red Hat Linux 6.2 and earlier, ntpd on 
Red Hat Linux 7.0) does not properly check the size of a buffer used to 
hold incoming data from the network.  Potentially, an attacker could gain 
root access by exploiting this weakness.

Potential damage is mitigated by the fact that the Network Time Daemon is 
not enabled by default.  If you are not using network time services, it 
may not even be installed. As a general rule, Red Hat encourages users to 
enable only those network services they actually need.

4. Solution:

To update all RPMs for your particular architecture, run:

rpm -Fvh [filenames]

where [filenames] is a list of the RPMs you wish to upgrade.  Only those
RPMs which are currently installed will be updated.  Those RPMs which are
not installed but included in the list will not be updated.  Note that you
can also use wildcards (*.rpm) if your current directly *only* contains the
desired RPMs.

Please note that this update is also available via Red Hat Network.  Many
people find this an easier way to apply updates.  To use Red Hat Network,
launch the Red Hat Update Agent with the following command:

up2date

This will start an interactive process that will result in the appropriate
RPMs being upgraded on your system.

5. Bug IDs fixed  (http://bugzilla.Red Hat.com/bugzilla for more info):

34813 - ntpd security hole

6. RPMs required:

Red Hat Linux 5.2:

SRPMS: 
ftp://updates.Red Hat.com/5.2/en/os/SRPMS/xntp3-5.93-14.src.rpm

alpha: 
ftp://updates.Red Hat.com/5.2/en/os/alpha/xntp3-5.93-14.alpha.rpm

i386: 
ftp://updates.Red Hat.com/5.2/en/os/i386/xntp3-5.93-14.i386.rpm

sparc: 
ftp://updates.Red Hat.com/5.2/en/os/sparc/xntp3-5.93-14.sparc.rpm

Red Hat Linux 6.2:

SRPMS: 
ftp://updates.Red Hat.com/6.2/en/os/SRPMS/xntp3-5.93-15.src.rpm

alpha: 
ftp://updates.Red Hat.com/6.2/en/os/alpha/xntp3-5.93-15.alpha.rpm

i386: 
ftp://updates.Red Hat.com/6.2/en/os/i386/xntp3-5.93-15.i386.rpm

sparc: 
ftp://updates.Red Hat.com/6.2/en/os/sparc/xntp3-5.93-15.sparc.rpm

Red Hat Linux 7.0:

SRPMS: 
ftp://updates.Red Hat.com/7.0/en/os/SRPMS/ntp-4.0.99k-15.src.rpm

alpha: 
ftp://updates.Red Hat.com/7.0/en/os/alpha/ntp-4.0.99k-15.alpha.rpm

i386: 
ftp://updates.Red Hat.com/7.0/en/os/i386/ntp-4.0.99k-15.i386.rpm


7. Verification:

MD5 sum                           Package Name
--------------------------------------------------------------------------
0d3566d34cd5bc9990a15a41be99e4c7 5.2/en/os/SRPMS/xntp3-5.93-14.src.rpm
aa851fdb72e9f6464e9688378617c9df 5.2/en/os/alpha/xntp3-5.93-14.alpha.rpm
176041bd0364ca91b6d7db3869c4a0a0 5.2/en/os/i386/xntp3-5.93-14.i386.rpm
9b224d8bd3640a6fbd37785c6c5d3ce2 5.2/en/os/sparc/xntp3-5.93-14.sparc.rpm
a83add134f54dd4fbdcfd0cef5929b43 6.2/en/os/SRPMS/xntp3-5.93-15.src.rpm
64d936dcf1fa8fe97a12b314923ae89c 6.2/en/os/alpha/xntp3-5.93-15.alpha.rpm
af43bc024a00586ef97265c7bf2e63df 6.2/en/os/i386/xntp3-5.93-15.i386.rpm
3f13de81debf2dc875d84c046596e27d 6.2/en/os/sparc/xntp3-5.93-15.sparc.rpm
b7f60c57e74179913ebc2dc1da04f410 7.0/en/os/SRPMS/ntp-4.0.99k-15.src.rpm
6334b7ba31606cfe04d98967adbf3350 7.0/en/os/alpha/ntp-4.0.99k-15.alpha.rpm
f67d135fd6ccadb9f36aeca4a429a9fa 7.0/en/os/i386/ntp-4.0.99k-15.i386.rpm

These packages are GPG signed by Red Hat, Inc. for security.  Our key
is available at:
     http://www.Red Hat.com/corp/contact.html

You can verify each package with the following command:
    rpm --checksig  

If you only wish to verify that each package has not been corrupted or
tampered with, examine only the md5sum with the following command:
    rpm --checksig --nogpg 

8. References:

BugTraq Message-ID <20010404222701.X91913@riget.scene.pl> 
http://www.eecis.udel.edu/~ntp/


Copyright(c) 2000, 2001 Red Hat, Inc.
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