Backers of proprietary software have, at times in the past, resorted to
claims that Linux and free software are the subject of more CERT advisories
than other systems. Such claims have been strikingly absent recently.
Since our detractors have apparently been too busy to tally up CERT's
output this year, we've decided to do it for them. Here's the full list of
CERT's 2004 "technical cyber security alerts":
Now, one can raise all sorts of complaints about this table. The logic
that assigns the Mozilla vulnerability to Linux could also, easily, have
charged it to Windows as well. The process by which CERT chooses
vulnerabilities worthy of "cyber security alerts" is poorly understood.
And so on.
There are seven vulnerabilities in the Linux column - and that is seven too
many. But that is far less than the count in the proprietary columns. The
Windows vulnerabilities include many which affect a large percentage of
users; instead, very few users were affected by most of the Linux
problems. The CERT advisory count is a flawed measure at best, but, within
its limits, it shows that things could be a lot worse.
Bugzilla versions prior to 2.16.7 have a vulnerability
which allows a remote user to remove keywords from a ticket even without
the necessary permissions. Such an action, however, would trigger the usual
e-mail detailing the changes, making it easy to discover what happened and
what was changed.
During an audit of the smb file system implementation within Linux, several
vulnerabilities were discovered ranging from out of bounds read accesses to
kernel level buffer overflows. See these advisories: Linux kernel
binfmt_elf loader vulnerabilities and
Memory leak in 2.4.27 kernel for more information.
ProZilla contains several exploitable buffer overflows in the code handling
the network protocols. A remote attacker could setup a malicious server
and entice a user to retrieve files from that server using ProZilla. This
could lead to the execution of arbitrary code with the rights of the user
running ProZilla.
According to an Apache
announcement, a vulnerability exists in the Apache HTTP server, version
1.3. The problem is a potential buffer overflow in the "get_tag" function
of Apache's SSI module "mod_include". It allows local users who can create
SSI documents to execute arbitrary code as the Apache run-time user via SSI
documents that trigger a content length calculation error.
Versions of Apache 2.0 prior to 2.0.53 contain a bug in the header
parsing code which can allow a remote denial of service attack given
sufficient bandwidth.
Aspell's word-list-compress utility fails to properly check bounds
when dealing with words that are more than 256 bytes long.
This can lead to arbitrary code execution by an attacker.
Leon Juranic discovered that BNC fails to do proper bounds checking
when checking server response. An attacker could exploit this to cause a
Denial of Service and potentially execute arbitrary code with the
permissions of the user running BNC.
compress and uncompress do not properly check bounds on command line
options, including the filename. Large parameters would trigger a buffer
overflow. By supplying a carefully crafted filename or other option, an
attacker could execute arbitrary code on the system. A local attacker could
only execute code with his own rights, but since compress and uncompress
are called by various daemon programs, this might also allow a remote
attacker to execute code with the rights of the daemon making use of
ncompress.
cyrus-sasl has a vulnerability involving a buffer overflow
in the digestmda5.c file. A remote attacker may be able
to compromise the system. Also, a local user may be able to
exploit a vulnerability by using the SASL_PATH environment
variable.
"fam" (file alteration monitor) watches files and directories for changes and lets interested applications know when something happens. This package has a flaw in its group handling that blocks some legitimate operations while, at the same time, exposing the names of files that should otherwise be invisible.
There is a vulnerability in the foomatic-filters package. This
vulnerability is due to insufficient checking of command-line parameters
and environment variables in the foomatic-rip filter. This vulnerability
may allow both local and remote attackers to execute arbitrary commands on
the print server with the permissions of the spooler.
A buffer overflow in the MSN protocol handler for gaim 0.79 to 1.0.1 allows
remote attackers to cause a denial of service (application crash) and
possibly execute arbitrary code via an "unexpected sequence of MSNSLP
messages" that results in an unbounded copy operation that writes to the
wrong buffer.
Jim Paris has discovered a cross-site scripting vulnerability in
Gallery. By sending a carefully crafted URL, an attacker can inject and
execute script code in the victim's browser window, and potentially
compromise the users gallery.
The gdk-pixbuf and gtk2 libraries contain vulnerabilities in their handling of BMP and XPM files which can lead to denial of service and, potentially, code execution attacks.
gettext insecurely creates temporary files in world-writeable directories
with predictable names. A local attacker could create symbolic links in
the temporary files directory, pointing to a valid file somewhere on the
filesystem. When gettext is called, this would result in file access with
the rights of the user running the utility, which could be the root user.
The GIMPS, SETI@home and ChessBrain applications have
installation vulnerabilities caused by installation with
improper file ownerships. User-owned files can be run with root
privileges on initialization.
Silvio Cesare discovered a potential information leak in glibc. It allows
LD_DEBUG on SUID binaries where it should not be allowed. This has various
security implications, which may be used to gain confidential information.
An attacker can gain the list of symbols a SUID application uses and their
locations and can then use a trojaned library taking precedence over those
symbols to gain information or perform further exploitation.
The catchsegv script in the glibc package has a symlink vulnerability
that may allow a local user to overwrite arbitrary
files with the permissions of the user that is running the script.
Several scripts packaged with gnome-vfs, using its "extfs" capability, have security flaws. These scripts tend not to be used on many systems, but their presence can still be a threat.
Recently, Trustix Secure Linux discovered a vulnerability in the groff
package. The utility "groffer" created a temporary directory in an
insecure way, which allowed exploitation of a race condition to create
or overwrite files with the privileges of the user invoking the
program.
GtkHTML is the HTML rendering widget used by the Evolution mail reader.
GtkHTML supplied with versions of Evolution prior to 1.2.4 contain a bug
when handling HTML messages. Alan Cox discovered that certain malformed
messages could cause the Evolution mail component to crash.
Trustix developers discovered insecure temporary file creation in
supplemental scripts in the gzip package which may allow local users
to overwrite files via a symlink attack.
The ImageMagick graphics library has several buffer overflow
vulnerabilities that allow an attacker to crash the reading process
by creating mal-formed video or image files in the AVI, BMP, or DIB format.
ImageMagick fails to do proper bounds checking when handling image
files with EXIF information. An attacker could use an image file with
specially-crafted EXIF information to cause arbitrary code execution with
the permissions of the user running ImageMagick. See this advisory for more
information.
Faheem Mitha noticed that the iptables command, an administration tool for
IPv4 packet filtering and NAT, did not always load the required modules on
its own as it was supposed to. This could lead to firewall rules not being
loaded on system startup. This caused a failure in connection with rules
provided by lokkit at least.
The kernel-utils package contains several utilities that can be used to
control the kernel or machine hardware. In Red Hat Linux 8.0 this package
contains user mode linux (UML) utilities.
The uml_net utility in kernel-utils packages with Red Hat Linux 8.0 was
incorrectly shipped setuid root. This could allow local users to control
certain network interfaces, add and remove arp entries and routes, and put
interfaces in and out of promiscuous mode.
All users of the kernel-utils package should update to these packages that
contain a version of uml_net that is not setuid root.
Alternatively, as a work-around to this vulnerability issue the following
command as root:
Several buffer overflows have been discovered in libgd's PNG handling
functions.
If an attacker tricked a user into loading a malicious PNG image, they
could leverage this into executing arbitrary code in the context of
the user opening image. Most importantly, this library is commonly
used in PHP. One possible target would be a PHP driven photo website
that lets users upload images. Therefore this vulnerability might lead
to privilege escalation to a web server's privileges.
Multiple buffer overflows in the gd graphics library (libgd) 2.0.21 and
earlier may allow remote attackers to execute arbitrary code via malformed
image files that trigger the overflows due to improper calls to the
gdMalloc function.
Yuuichi Teranishi discovered a flaw in libxml2 versions prior to 2.6.6.
When fetching a remote resource via FTP or HTTP, libxml2 uses special
parsing routines. These routines can overflow a buffer if passed a very
long URL. If an attacker is able to find an application using libxml2 that
parses remote resources and allows them to influence the URL, then this
flaw could be used to execute arbitrary code.
libxml2 prior to version 2.6.14 has multiple buffer overflow
vulnerabilities, if a local user passes a specially crafted
FTP URL, arbitrary code may be executed.
Trustix Secure Linux discovered a vulnerability in a supplemental script of
the lvm10 package. The program "lvmcreate_initrd" created a temporary
directory in an insecure way, which could allow a symlink attack to create
or overwrite arbitrary files with the privileges of the user invoking the
program.
Several vulnerabilities exist in the Mozilla web browser and derived
products, the most serious of which could allow a remote attacker to
execute arbitrary code on an affected system. See the CERT advisory for details.
A vulnerability was discovered in mpg321, a command-line mp3 player,
whereby user-supplied strings were passed to printf(3) unsafely. This
vulnerability could be exploited by a remote attacker to overwrite
memory, and possibly execute arbitrary code. In order for this
vulnerability to be exploited, mpg321 would need to play a malicious
mp3 file (including via HTTP streaming).
Several problems have been discovered in MySQL. Oleksandr Byelkin noticed
that ALTER TABLE ... RENAME checks CREATE/INSERT rights of the old table
instead of the new one. (CAN-2004-0835) Lukasz Wojtow noticed a buffer
overrun in the mysql_real_connect function. (CAN-2004-0836) Dean Ellis
noticed that multiple threads ALTERing the same (or different) MERGE tables
to change the UNION can cause the server to crash or stall. (CAN-2004-0837)
Michal Zalewski discovered a bug in the netkit-telnet server (telnetd)
whereby a remote attacker could cause the telnetd process to free an
invalid pointer. This causes the telnet server process to crash, leading
to a straightforward denial of service (inetd will disable the service if
telnetd is crashed repeatedly), or possibly the execution of arbitrary code
with the privileges of the telnetd process (by default, the 'telnetd'
user).
netpbm is graphics conversion toolkit made up of a large number of
single-purpose programs. Many of these programs were found to create
temporary files in an insecure manner, which could allow a local
attacker to overwrite files with the privileges of the user invoking a
vulnerable netpbm tool.
From the advisory:
"During a pen-test we stumbled across a nasty bug in OpenSSH-portable
with PAM support enabled (via the --with-pam configure script switch). This
bug allows a remote attacker to identify valid users on vulnerable systems,
through a simple timing attack. The vulnerability is easy to exploit and
may have high severity, if combined with poor password policies and other
security problems that allow local privilege escalation."
The der_chop script in openssl has a temp file vulnerability that may allow
an attacker to overwrite arbitrary files with the permissions that
the script is running under.
Trustix Secure Linux has discovered some vulnerabilities in the perl
package. The utility "instmodsh", the Perl package "PPPort.pm", and several
test scripts (which are not shipped and only used during build) created
temporary files in an insecure way, which could allow a symlink attack to
create or overwrite arbitrary files with the privileges of the user
invoking the program, or building the perl package, respectively.
Stefan Esser has issued an advisory regarding a
remotely exploitable hole in PHP (through version 4.3.7). If the
memory_limit feature is in use (as it should be, to prevent denial
of service attacks), allocation failures can be forced at highly
inopportune times, and those failures can be exploited to execute arbitrary
code. The exploit is described as "quite easy," and it can be done
regardless of whether Apache1 or Apache2 is in use. Upgrading to PHP 4.3.8 fixes the
problem; yesterday's PHP 5.0 release also contains the fix (but the
final release candidate did not).
The make_oidjoins_check script insecurely creates temporary files in
world-writeable directories with predictable names. A local attacker could
create symbolic links in the temporary files directory, pointing to a valid
file somewhere on the filesystem. When make_oidjoins_check is called, this
would result in file overwrite with the rights of the user running the
utility, which could be the root user.
Max Vozeler discovered a vulnerability in pppoe, the PPP over Ethernet
driver from Roaring Penguin. When the program is running setuid root
(which is not the case in a default Debian installation), an attacker
could overwrite any file on the file system.
The upstream developers of Ruby have corrected a problem in the CGI
module for this language. Specially crafted requests could cause an
infinite loop and thus cause the program to eat up cpu cycles.
According to this Samba advisory a remote
attacker could cause an smbd process to consume abnormal amounts of system
resources due to an input validation error when matching filenames
containing wildcard characters. Versions of Samba 3.0.x up to and
including 3.0.7 are vulnerable.
There is also an advisory about possible
buffer overruns in smbd.
The shadow user account utilities have a potential problem with
the chfn and chsh utilities that may allow unauthorized users to
modify account properties.
sharutils contains two buffer overflows. Ulf Harnhammar discovered a buffer
overflow in shar.c, where the length of data returned by the wc command is
not checked. Florian Schilhabel discovered another buffer overflow in
unshar.c. An attacker could exploit these vulnerabilities to execute
arbitrary code as the user running one of the sharutils programs.
SpamAssassin contains an unspecified Denial of Service vulnerability. By
sending a specially crafted message an attacker could cause a Denial of
Service attack against the SpamAssassin service.
Subversion has a remote Denial of Service vulnerability
that may allow a server that runs svnserve to execute
arbitrary code. See this advisory for more information.
Versions of sudo prior to 1.6.8p2 fail to properly sanitize the environment prior to running shell scripts; this failure can be exploited by a sudo user to subvert scripts and obtain shell access. See the 1.6.8p2 announcement for more information.
The tar utility does not properly filter file names containing
"../", meaning that a hostile archive can, if unpacked by an
unsuspecting user, overwrite any file that is writable by that user. GNU
tar versions 1.13.19 and earlier are vulnerable; unzip through version 5.42
has the same vulnerability.
The tiff library contains several buffer overflows which may be exploited
by way of maliciously-crafted image files. See this advisory for more information.
The unarj uncompression utility has a buffer overflow vulnerability
from handling long file names in an archive. An attacker can
cause unarj to crash or execute arbitrary code.
WordPress: HTTP response splitting and XSS vulnerabilities
Package(s):
wordpress
CVE #(s):
Created:
October 14, 2004
Updated:
December 20, 2004
Description:
WordPress is vulnerable to HTTP response splitting and cross-site scripting
attacks, due to the lack of input validation in the administration panel
scripts. A malicious user could inject arbitrary response data, leading to
content spoofing, web cache poisoning and other cross-site scripting or
HTTP response splitting attacks. This could result in compromising the
victim's data or browser.
XChat is vulnerable to a stack overflow that may allow a remote attacker to
run arbitrary code. The SOCKS 5 proxy code in XChat is vulnerable to a
remote exploit. Users would have to be using XChat through a SOCKS 5
server, enable SOCKS 5 traversal which is disabled by default and also
connect to an attacker's custom proxy server. This vulnerability may allow
an attacker to run arbitrary code within the context of the user ID of the
XChat client.
Shaun Colley discovered a problem in xine-ui, the xine video player
user interface. A script contained in the package to possibly remedy
a problem or report a bug does not create temporary files in a secure
fashion. This could allow a local attacker to overwrite files with
the privileges of the user invoking xine.
Several xpdf integer overflow vulnerabilities can be exploited via a
mal-formed PDF document. Similar vulnerabilities can be found in kpdf and
in cupsys which share code. Additional information can be found in this KDE security advisory.
Multiple arithmetic overflows have been detected in the image
processing code of zgv. An attacker could entice a user to open a
specially-crafted image file, potentially resulting in execution of
arbitrary code with the rights of the user running zgv. See this BugTraq advisory
for more information.
HexView discovered a buffer overflow in the zip package. The overflow is
triggered by creating a ZIP archive of files with very long path
names. This vulnerability might result in execution of arbitrary code with
the privileges of the user who calls zip. This flaw may lead to privilege
escalation on systems which automatically create ZIP archives of user
supplied files, like backup systems or web applications.
Rick Moen has put together (and recently updated) a comprehensive
FAQ on Linux and viruses. It includes a comprehensive list of Linux
viruses and worms. "By and large, you can be hit at all only by
being really dumb. By and large, you can suffer system (root) compromise
from malware only by being mind-bogglingly dumb."
