'nfs-utils' Buffer Overflow May Let Remote Users Execute Arbitrary Code
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SecurityTracker Alert ID: 1007187 |
SecurityTracker URL: http://securitytracker.com/id/1007187
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CVE Reference:
CVE-2003-0252
(Links to External Site)
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Updated: Jun 14 2008
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Original Entry Date: Jul 14 2003
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Impact:
Denial of service via network, Execution of arbitrary code via network, User access via network
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Fix Available: Yes Vendor Confirmed: Yes
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Version(s): 1.0.3 and prior versions
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Description:
An off-by one buffer overflow vulnerability was reported in 'nfs-utils'. A remote user may be able to execute arbitrary code on the target system.
Janusz Niewiadomski of iSEC Security Research reported that a remote user can send a specially crafted request to the rpc.mountd daemon to trigger an overflow in the xlog() logging function. If the user-supplied string is 1023 bytes or longer, the trailing null '\0' byte is written beyond the end of the buffer.
According to the report, a remote user can cause the daemon to crash or execute arbitrary code with the privileges of the daemon. However, Red Hat reported in advisory RHSA-2003:206-01 that "it is not believed that this bug could lead to remote arbitrary code execution."
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Impact:
A remote user can send a specially crafted NFS request to cause the rpc.mountd daemon to crash or execute arbitrary code. The arbitrary code will run with the privileges of the daemon.
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Solution:
The vendor has released a fixed version (1.0.4), available at:
http://sourceforge.net/projects/nfs/
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Vendor URL: sourceforge.net/projects/nfs/ (Links to External Site)
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Cause:
Boundary error
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Underlying OS: Linux (Any)
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Message History:
This archive entry has one or more follow-up message(s) listed below.
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Source Message Contents
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Subject: [VulnWatch] Linux nfs-utils xlog() off-by-one bug
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-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Synopsis: Linux nfs-utils xlog() off-by-one bug
Product: nfs-utils
Version: <= 1.0.3
Vendor: http://sourceforge.net/projects/nfs/
URL: http://isec.pl/vulnerabilities/
CVE: CAN-2003-0252
Author: Janusz Niewiadomski <funkysh@isec.pl>
Date: July 14, 2003
Issue:
======
Linux NFS utils package contains remotely exploitable off-by-one bug.
A local or remote attacker could exploit this vulnerability by sending
specially crafted request to rpc.mountd daemon.
Details:
========
An off-by-one bug exist in xlog() function which handles logging of
requests. An overflow occurs when function is trying to add missing
trailing newline character to logged string.
Due to miscalculation, if a string passed to the functions is equal
or longer than 1023 bytes, the '\0' byte will be written beyond the
buffer:
- ------8<------cut-here------8<------
char buff[1024];
...
va_start(args, fmt);
vsnprintf(buff, sizeof (buff), fmt, args);
va_end(args);
buff[sizeof (buff) - 1] = 0;
if ((n = strlen(buff)) > 0 && buff[n-1] != '\n') {
buff[n++] = '\n'; buff[n++] = '\0';
}
- ------8<------cut-here------8<------
Impact:
=======
Local or remote attacker which is capable to send RPC request to
vulnerable mountd daemon could execute artitrary code or cause
denial of service.
Status:
=======
Vendor has been notified on June 10, 2003. The fix is incorporated
in recent 1.0.4 release of nfs-utils.
The Mitre Corp.'s Common Vulnerabilities and Exposures (CVE) Project
has assigned the identification number CAN-2003-0252 to this issue.
- --
Janusz Niewiadomski
iSEC Security Research
http://isec.pl/
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