Security software is, as a general rule, supposed to make a system more
secure. So it is always discouraging when security code, instead, opens up
new holes. The PaX patches are
intended to harden the Linux kernel against various sorts of attacks; its
developers have, at times, been quite harsh in their criticism of security
in the mainline kernel. But, as this
advisory shows, the PaX code, too, is not without its troubles.
One of the techniques used by PaX is VMA mirroring. The
PaX code tries to defeat various types of code injection attacks by
completely separating the instruction and data areas of memory as seen by
Linux processes. The idea is that, even if an attacker is able to overrun
a buffer and direct the processor to execute the resulting code, the attack
will be foiled by the processor's segmentation hardware. Any part of
memory which can be accessed via a data pointer is simply not accessible as
code.
The problem is that some code segments in an executable file contain data
as well - constant strings and such. So, when an executable ELF section is
mapped into the code segment, it must also be "mirrored" in the data
segment. This mirroring is accomplished by creating a special sort of
virtual memory area (VMA) which refers to the same physical pages and
backing store as code VMA, but which resides in the data portion of the
address space.
The details of the exploit have not yet been released. From a quick
reading of the PaX patches before and after the fix, it would appear that
the PaX code did not adequately restrict the changes user space could make
to the mirrored VMAs. The resulting inconsistencies in the kernel's
representation of the address space could then be exploited to run
arbitrary code.
The advisory notes that this vulnerability "...pretty much destroys
what PaX has always stood and been trusted for." So the author is
taking his marbles and going home; PaX will be discontinued at the end of
this month. Certainly, introducing an exploitable hole into a
security-related patch, where it lurked for a year and a half, could harm
the trust users have in that patch. But giving up and leaving those users
completely unsupported into the future seems likely to cause rather more
damage. Bugs happen, even in the most carefully-written code. The best
thing to do is to fix them and get on with life.
Several vulnerabilities have been discovered in abuse, the SDL port of
the Abuse action game. Erik Sjölund discovered several buffer overflows in
the command line handling, which could lead to the execution of arbitrary
code with elevated privileges since it is installed setuid root. Steve
Kemp discovered that that abuse creates some files without dropping
privileges first, which may lead to the creation and overwriting of
arbitrary files.
Davide Madrisan has discovered that the dcopidlng script creates temporary
files in a world-writable directory 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 dcopidlng is
executed, this would result in the file being overwritten with the rights
of the user running the utility, which could be the root user.
Tavis Ormandy of the Gentoo Linux Security Audit Team identified a flaw
in the Hashcash utility that an attacker could expose by specifying a
malformed reply address. Successful exploitation would permit an attacker
to disrupt Hashcash users, and potentially execute arbitrary code.
The Helix Player 1.0 media player has two buffer overflows
that can be exploited by playing specially crafted
SMIL and WAV files. This can allow a remote attacker to
execute code with the user's permissions.
The ImageMagick file
name handling code has a format string vulnerability.
Specially crafted file names can be used to crash ImageMagick
and possibly execute arbitrary code.
The kdenetwork networking applications package has a bug
with the handling of privileged file descriptors in kppp.
A local user can use this to modify the /etc/hosts
and /etc/resolv.conf files, allowing them to
spoof domain information.
Victor Ashik discovered a heap based buffer overflow in less, caused by
a patch added to the less package in Red Hat Linux 9. An attacker could
construct a carefully crafted file that could cause less to crash or
possibly execute arbitrary code when opened.
Sylvain Defresne discovered that the EXIF library did not properly
validate the structure of the EXIF tags. By tricking a user to load an
image with a malicious EXIF tag, an attacker could exploit this to
crash the process using the library, or even execute arbitrary code
with the privileges of the process.
mlterm is vulnerable to an integer overflow that can be triggered by
specifying a large image file as a background. This only effects users
that have compiled mlterm with the 'gtk' USE flag, which enables
gdk-pixbuf support.
phpMyAdmin contains multiple vulnerabilities that could lead to command
execution, XSS issues and bypass of security restrictions. See PMASA-2005-1
and PMASA-2005-2
for details.
The RealPlayer media player has two buffer overflows
that can be exploited by playing specially crafted
SMIL and WAV files. This can allow a remote attacker to
execute code with the user's permissions.
A race condition in Squid 2.5.STABLE7 to 2.5.STABLE9, when using the
Netscape Set-Cookie recommendations for handling cookies in caches, may
cause Set-Cookie headers to be sent to other users, which allows attackers
to steal the related cookies.
Tavis Ormandy of the Gentoo Linux Security Audit Team identified a flaw
in the handling of image filenames by xv. Successful exploitation would
require a victim to process a specially crafted image with a malformed
filename, potentially resulting in the execution of arbitrary code.
The GNU a2ps utility fails to properly sanitize filenames, which can be
abused by a malicious user to execute arbitrary commands with the
privileges of the user running the vulnerable application. More
information at Security
Focus.
Ulf Härnhammar from the Debian Security Audit Project discovered a
format string vulnerability in bidwatcher, a tool for watching and
bidding on eBay auctions. This problem can be triggered remotely by a
web server of eBay, or someone pretending to be eBay, sending certain
data back. As of version 1.3.17 the program uses cURL and is not
vulnerable anymore.
Bastian Blank found a vulnerability in bsmtpd, a batched SMTP mailer for
sendmail and postfix. Unsanitized addresses can cause the execution
of arbitrary commands during alleged mail delivery.
Florian Westphal discovered that cmd5checkpw is installed setuid
cmd5checkpw but does not drop privileges before calling execvp(), so
the invoked program retains the cmd5checkpw euid. Local users that know at
least one valid /etc/poppasswd user/password combination can read the
/etc/poppasswd file.
Multiple stack-based buffer overflows in libcURL and cURL 7.12.1, and
possibly other versions, allow remote malicious web servers to execute
arbitrary code via base64 encoded replies that exceed the intended buffer
lengths when decoded.
Cyrus-imapd, prior to version 2.2.12, contains several buffer overflows which could be exploited by an (authenticated) attacker to run code on the server system.
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.
Max Vozeler discovered a format string vulnerability in the "movemail"
utility of Emacs. By sending specially crafted packets, a malicious
POP3 server could cause a buffer overflow, which could be exploited to
execute arbitrary code with the privileges of the user and the "mail"
group.
Erik Sjölund has discovered several security relevant problems in enscript,
a program to convert ASCII text into Postscript and other formats.
Unsanitized input can cause the execution of arbitrary commands via EPSF
pipe support. Due to missing sanitizing of filenames it is possible that a
specially crafted filename can cause arbitrary commands to be executed.
Multiple buffer overflows can cause the program to crash.
Max Vozeler discovered an integer overflow in camel-lock-helper. A
user-supplied length value was not validated, so that a value of -1
caused a buffer allocation of 0 bytes; this buffer was then filled by
an arbitrary amount of user-supplied data. A local attacker or a malicious
POP3 server could exploit this to execute arbitrary code with root
privileges (because camel-lock-helper is installed as setuid root).
The f2c fortran to C translator has a vulnerability due to
insecure opening of temporary files. A local attacker can use this
to launch a symlink attack.
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.
The Gaim client freezes when receiving certain invalid messages and crashes
when receiving specific malformed HTML. See this Secunia Advisory for
additional information.
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.
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.
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.
Michael Krax discovered that ht://Dig fails to validate the 'config'
parameter before displaying an error message containing the parameter.
This flaw could allow an attacker to conduct cross-site scripting
attacks.
According to this iDEFENSE advisory,
ImageMagick is vulnerable to a heap overflow when decoding .psd image
files. This could be remotely exploited allowing an attacker to execute
arbitrary code.
A buffer overflow flaw was found in the c-client IMAP client. An attacker
could create a malicious IMAP server that if connected to by a victim could
execute arbitrary code on the client machine.
Thiago Macieira discovered a vulnerability in the kioslave library,
which is part of kdelibs, which allows a remote attacker to execute
arbitrary FTP commands via an ftp:// URL that contains an URL-encoded
newline before the FTP command.
Javier Fernández-Sanguino Peña from the Debian Security Audit Project
discovered that the DBI library, the Perl5 database interface, creates
a temporary PID file in an insecure manner. This can be exploited by a
malicious user to overwrite arbitrary files owned by the person
executing the parts of the library.
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.
Michael Kerrisk noticed an insufficient permission checking in the shmctl()
function. Any process was permitted to lock/unlock any System V shared
memory segment that fell within the the RLIMIT_MEMLOCK limit (that is the
maximum size of shared memory that unprivileged users can acquire). This
allowed am unprivileged user process to unlock locked memory of other
processes, thereby allowing them to be swapped out. Usually locked shared
memory is used to store passphrases and other sensitive content which must
not be written to the swap space (where it could be read out even after a
reboot). (CAN-2005-0176)
OGAWA Hirofumi noticed that the table sizes in nls_ascii.c were incorrectly
set to 128 instead of 256. This caused a buffer overflow in some cases
which could be exploited to crash the kernel. (CAN-2005-177)
A race condition was found in the terminal handling of the "setsid()" function, which is used to start new process sessions. (CAN-2005-178)
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.
Florian Weimer discovered a cross-site scripting vulnerability in
mailman's automatically generated error messages. An attacker could
craft an URL containing JavaScript (or other content embedded into
HTML) which triggered a mailman error page. When an unsuspecting user
followed this URL, the malicious content was copied unmodified to the
error page and executed in the context of this page.
The "private" module in the mailman mailing list manager fails to sanitize path names adequately. An attacker could exploit this vulnerability to retrieve private information, including passwords and private list archives.
Midnight commander has multiple vulnerabilities including
format string vulnerabilities, buffer overflows, a buffer underflow,
and a memory deallocation error. An attacker can use these to
run arbitrary code with the permission of the user.
A security audit of the MediaWiki project discovered that MediaWiki is
vulnerable to several cross-site scripting and cross-site request
forgery attacks, and that the image deletion code does not sufficiently
sanitize input parameters.
mod_python has a vulnerability in the publisher handler that may allow
a remote user to use a specially crafted URL to allow access to
objects that should be protected. An information leak can result.
According to this iDEFENSE advisory, remote
exploitation of a design error in Mozilla 1.7.3 and Firefox 1.0 may allow
an attacker to cause heap corruption, resulting in execution of arbitrary
code.
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)
Javier Fernández-Sanguino Peña noticed that the "mysqlaccess" program
created temporary files in an insecure manner. This could allow a
symbolic link attack to create or overwrite arbitrary files with the
privileges of the user invoking the program.
Jonathan Rockway discovered that NASM-0.98.38 has an unprotected
vsprintf() to an array in preproc.c. This code vulnerability may lead
to a buffer overflow and potential execution of arbitrary code.
Erik Sjolund discovered two vulnerabilities in the programs bundled
with ncpfs: there is a potentially exploitable buffer overflow in
ncplogin (CAN-2005-0014), and due to a flaw in nwclient.c, utilities
using the NetWare client functions insecurely access files with
elevated privileges (CAN-2005-0013).
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).
Arjan van de Ven discovered a buffer overflow in rquotad on 64bit
architectures; an improper integer conversion could lead to a buffer
overflow. An attacker with access to an NFS share could send a specially
crafted request which could then lead to the execution of arbitrary code.
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.
There are two vulnerabilities with perl when it is used in a setuid mode. The PERLIO_DEBUG environment variable can be used to overwrite arbitrary files; there is also an associated buffer overflow which can be exploited to gain root access.
PHP has an out of bounds memory write access vulnerability and
an integer overflow/underflow problem. See the PHP 4.3.10 Release Announcement for details.
It was discovered that phpBB contains a flaw in the session handling
code and a path disclosure bug. AnthraX101 discovered that phpBB allows
local users to read arbitrary files, if the "Enable remote avatars" and
"Enable avatar uploading" options are set (CAN-2005-0259). He also
found out that incorrect input validation in "usercp_avatar.php" and
"usercp_register.php" makes phpBB vulnerable to directory traversal
attacks, if the "Gallery avatars" setting is enabled (CAN-2005-0258).
phpWebSite: arbitrary PHP execution and path disclosure
Package(s):
phpwebsite
CVE #(s):
Created:
March 1, 2005
Updated:
March 2, 2005
Description:
NST discovered that, when submitting an announcement, uploaded files
aren't correctly checked for malicious code. They also found out that
phpWebSite is vulnerable to a path disclosure. A remote attacker can
exploit this issue to upload files to a directory within the web root. By
calling the uploaded script the attacker could then execute arbitrary PHP
code with the rights of the web server. By passing specially crafted
requests to the search module, remote attackers can also find out the full
path of PHP scripts.
Jean-Samuel Reynaud noticed a programming error in the IPv6 handling code
of Postfix when /proc/net/if_inet6 is not available. If "permit_mx_backup"
was enabled in the "smtpd_recipient_restrictions", Postfix turned into an
open relay, i. e. erroneously permitted the delivery of arbitrary mail to
any MX host which has an IPv6 address.
postgresql has a vulnerability in which the EXECUTE privilege may
not be checked on custom functions. This may allow any database user to
circumvent the EXECUTE restriction on functions.
Two vulnerabilities have been discovered in the PSCP and PSFTP clients,
which can be triggered by the SFTP server itself. See this iDEFENSE advisory for details.
Python versions 2.2 and 2.3 has a vulnerability in the
SimpleXMLRPCServer module which may allow
remote users to read or change function internals via the
im_* and func_* attributes.
Tavis Ormandy of the Gentoo Linux Security Audit Team has discovered
that Qt searches for shared libraries in an untrusted, world-writable
directory. A local attacker could create a malicious shared object that
would be loaded by Qt, resulting in the execution of arbitrary code with
the privileges of the Qt application.
The per-user configuration file ~/.reportbugrc was created
world-readable. If it contained email smarthost passwords, these were
readable by any other user on the computer storing the home directory. If
users have ~/.reportbugrc files with SMTP passwords, the permissions should
be manually changed: chmod 600 .reportbugrc
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.
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.
Several vulnerabilities have been discovered in Squid, including cache
pollution/poisoning via HTTP response splitting, larger than normal WCCP
packet could overflow a buffer, and more.
Handling of certain DNS responses trigger assertion failures. By returning
a specially crafted DNS response an attacker could cause Squid to crash by
triggering an assertion failure.
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.
Ulf Harnhammar discovered that UnAce suffers from buffer overflows when
testing, unpacking or listing specially crafted ACE archives
(CAN-2005-0160). He also found out that UnAce is vulnerable to
directory traversal attacks, if an archive contains "./.." sequences or
absolute filenames (CAN-2005-0161).
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.
xpdf has a
potential buffer overflow problem caused by insufficient input validation.
A specially crafted PDF file can allow an
attacker to execute code with privileges of the xpdf user.
The patch for integer overflow vulnerabilities in Xpdf 2.0 and 3.0
(CAN-2004-0888) is incomplete for 64-bit architectures on certain Linux
distributions such as Red Hat, which could leave Xpdf users exposed to the
original vulnerabilities.
