A recent
announcement about adding
Sender Policy Framework (SPF) capabilities
to the machine hosting the linux-kernel mailing list (lkml) has sparked a
lively debate.
The first step, it seems, is to add an SPF record for
vger.kernel.org and later this summer to enable SPF checking on incoming
email. Both steps are controversial and the majority of posters seem to
be against the change, but Matti Aarnio, one of the postmasters
for vger, plans to go ahead with the changes.
SPF is a technique that allows a domain to specify which hosts are allowed
to send email that have an envelope sender (i.e. SMTP MAIL FROM) using that
domain. A domain administrator adds a TXT record to the DNS entry for
the domain that describes all hosts allowed to send mail. This allows
receiving Mail Transfer Agents (MTAs) to look up the SPF record and
determine whether the domain
in the envelope has been forged -- at least in theory.
Unfortunately, there are a number of problems with this scheme, most having
to do with email forwarding. Consider the case where a user has a yahoo.com
email account that they are forwarding to their ISP. When yahoo forwards
email that it receives, it uses the original envelope sender, but that domain
has almost certainly not listed yahoo.com as an authorized sender. The
same issue occurs if a user is trying to use their yahoo.com email as
the sender, but are required to use their ISP's SMTP server. In that case,
Yahoo will rightly not have the ISP listed as a legitimate sender for
their domain.
The SPF folks have suggested
solutions for these
problems, but many of them require fundamental changes in how MTAs operate.
The Sender Rewriting Scheme
(SRS) proposal
in particular breaks longstanding email tradition by having forwarding
MTAs change the envelope sender as they forward email. Opponents of SPF
not only argue that changing this tradition is a bad idea, but also that it
is very unlikely to be widely implemented any time soon. Additionally,
Mail User Agents (MUAs) would need to learn about SRS encoding in order to
parse sender addresses for filtering email at the user end.
SPF does provide a way to definitively determine that an email is
coming from
an authorized host, but failing the SPF check does not in any way imply that
the email is invalid, as the mail could have been forwarded by a non-SRS
compliant MTA.
The main benefit for domains that publish SPF
records may be a reduction in the blowback from a 'joe job' (a spammer
uses a victim domain as the sender on a large amount of spam, some of which
bounces, leaving the victim to deal with all the bounce messages).
Opponents
point out that
because of the forwarding problems, publishing an SPF record for your
domain essentially asks other MTAs to mark perfectly valid mail as suspicious
at best and forged at worst. Worse yet, some mail administrators are
configuring their MTAs to reject mail that fails SPF checking.
For the lkml, the immediate impact will be minimal, but still annoying to
some. People who have subscribed using addresses that are forwarded to
SPF-checking ISPs may no longer receive emails from the list. Some list
archiving software may also be affected. Once SPF checking is enabled, some
users may find their mail getting rejected depending on how strictly
the SPF policy is enforced. Expect another hue and cry on the lkml when
and if that happens.
A denial of service vulnerability has been found in the function for
encoding email addresses. Addresses containing a '=' before the '@'
character caused the Courier to hang in an endless loop, rendering the
service unusable.
The FreeType library has several integer overflow vulnerabilities.
If a user can be tricked into installing a specially
crafted font file, arbitrary code can be executed with the privilege
of the user.
gdm has a privilege escalation vulnerability that is tied to the
face browser feature. If face browser is enabled, arbitrary users
can access the gdm configuration screen, a feature that is normally
accessible only to root. Other user accounts, and possibly the root
account can then be subverted.
Joxean Koret discovered several cross-site scripting vulnerabilities in
Gforge, an online collaboration suite for software development, which
allow injection of web script code.
Tavis Ormandy of the Gentoo Linux Auditing Team discovered that the
vulnerable JPEG library ebuilds compile JPEG without the --maxmem feature
which is not recommended. By enticing a user to load a specially crafted
JPEG image file an attacker could cause a denial of service, due to memory
exhaustion.
OpenLDAP is vulnerable to a stack-based buffer overflow in the
st.c file from slurpd. Attackers may be able to use a long hostname
to execute arbitrary code.
Tor, an anonymizing communication service implementation, has
multiple vulnerabilities including a buffer overflow, a denial of
service vulnerability and an information leak problem.
A vulnerability has been discovered in webcalendar, a PHP-based multi-user
calendar, that allows a remote attacker to execute arbitrary PHP code when
register_globals is turned on.
WordPress insufficiently checks the format of cached username data. An
attacker could exploit this vulnerability to execute arbitrary commands by
sending a specially crafted username. As of Wordpress 2.0.2 the user data
cache is disabled as the default.
Federico L. Bossi Bonin discovered a buffer overflow in the HTTP input
module. By tricking an user into opening a malicious remote media
location, a remote attacker could exploit this to crash Xine library
frontends (like totem-xine, gxine, or xine-ui) and possibly even
execute arbitrary code with the user's privileges.
Several format string vulnerabilities have been discovered in xine-ui,
the user interface of the xine video player, which may cause a denial
of service.
Hendrik Weimer discovered that specially crafted web requests can
cause awstats, a powerful and featureful web server log analyzer, to
execute arbitrary commands.
The GNU Binutils has a buffer overflow vulnerability in libbfd.
Maliciously crafted Tektronix Hex Format files with improper length
characters can cause a crash and possibly lead to the execution of
arbitrary code.
Damian Put discovered that Blender did not properly validate a 'length'
value in .blend files. Negative values led to an insufficiently sized
memory allocation. By tricking a user into opening a specially crafted
.blend file, this could be exploited to execute arbitrary code with the
privileges of the Blender user.
The BusyBox 1.1.1 passwd command does not use a proper salt when generating
passwords. This would create an instance where a brute force attack could
take very little time.
A race condition in bzip2 1.0.2 and earlier allows local users to modify
permissions of arbitrary files via a hard link attack on a file while it is
being decompressed, whose permissions are changed by bzip2 after the
decompression is complete. Also specially crafted bzip2 archives may cause
an infinite loop in the decompressor.
From the Debian-Testing alert: Mehdi Oudad "deepfear" and Kevin Fernandez "Siegfried" from the Zone-H
Research Team discovered a buffer overflow in kkstrtext.h of the ktools
library, which is included in (at least) centericq and motor.
Richard Harms discovered that cpio did not sufficiently validate file
properties when creating archives. Files with e. g. a very large size
caused a buffer overflow. By tricking a user or an automatic backup
system into putting a specially crafted file into a cpio archive, a
local attacker could probably exploit this to execute arbitrary code
with the privileges of the target user (which is likely root in an
automatic backup system).
The Vixie cron daemon does not check the return code from setuid(); if that call can be made to fail, a local attacker may be able to execute commands as root.
A buffer overflow in Cscope 15.5, and possibly multiple overflows, allows
remote attackers to execute arbitrary code via a C file with a long
#include line that is later browsed by the target.
Heap-based buffer overflow in cURL and libcURL 7.15.0 through 7.15.2 allows
remote attackers to execute arbitrary commands via a TFTP URL (tftp://)
with a valid hostname and a long path.
Cyrus-SASL contains an unspecified vulnerability in the DIGEST-MD5
process that could lead to a Denial of Service. An attacker could possibly
exploit this vulnerability by sending specially crafted data stream to the
Cyrus-SASL server, resulting in a Denial of Service even if the attacker is
not able to authenticate.
The dia drawing utility suffers from several format string vulnerabilities exploitable via a maliciously crafted dia file - or a file with a well-chosen name.
The Dovecot imap server contains a directory traversal vulnerability which could be exploited by authenticated users to read files other than their mailboxes.
There are multiple
vulnerabilities in Firefox and related products including Thunderbird,
SeaMonkey and the Mozilla Suite. This CERT
Advisory contains additional information.
Tavis Ormandy of the Gentoo Linux Security Audit Team discovered an integer
overflow in the BFD library, resulting in a heap overflow. A review also
showed that by default, gdb insecurely sources initialization files from
the working directory. Successful exploitation would result in the
execution of arbitrary code on loading a specially crafted object file or
the execution of arbitrary commands.
A format string vulnerability has been discovered in gedit. Calling
the program with specially crafted file names caused a buffer
overflow, which could be exploited to execute arbitrary code with the
privileges of the gedit user.
zgrep in gzip before 1.3.5 does not handle shell metacharacters like '|'
and '&' properly when they occurred in input file names. This could be
exploited to execute arbitrary commands with user privileges if zgrep is
run in an untrusted directory with specially crafted file names.
The ImageMagick DisplayImageCommand has a heap overflow vulnerability.
If an maliciously created unexpanded glob is passed to ImageMagick,
a heap overflow can result.
ipsec-tools has a remote
denial of service vulnerability in the racoon daemon.
If racoon is running in aggressive mode, it fails to check all peer
payloads during
When the daemon the IKE negotiation phase, allowing a malicious peer
to crash the daemon. One should always be careful around aggressive racoons.
The kdebase package (and kcheckpass in particular) found in KDE versions 3.2.0 through 3.4.2 suffers from a lock file handling error which can enable a local attacker to obtain root access. See this advisory for details.
Kate / Kwrite, as shipped with KDE 3.2.x up to including 3.4.0, creates a file backup before saving a modified file. These backup files are created with default permissions, even if the original file had more strict permissions set. See this advisory for more information.
Multiple vulnerabilities in the Linux have been found.
An error in the Stream Control Transmission Protocol (SCTP) code that
uses incorrect state table entries when certain ECNE chunks are received in
CLOSED state, could be exploited by attackers to cause a kernel panic via a
specially crafted packet.
An error exist when handling incoming IP-fragmented SCTP control
chunks, which could be exploited by attackers to cause a kernel panic via a
specially crafted packet.
Linux SCTP (lksctp) allows remote attackers to cause a denial of
service (infinite recursion and crash) via a packet that contains two or
more DATA fragments, which causes an skb pointer to refer back to itself
when the full message is reassembled, leading to infinite recursion in the
sctp_skb_pull function
Linux SCTP (lksctp) allows remote attackers to cause a denial of
service (deadlock) via a large number of small messages to a receiver
application that cannot process the messages quickly enough, which leads to
"spillover of the receive buffer."
A vulnerability has been identified due to an input validation error
when processing arguments containing backslash ("\\") characters passed to
certain commands (e.g. "cd"), which could be exploited by authenticated
attackers to escape chroot restrictions for a CIFS or SMBFS mounted
filesystem.
The 2.6.12 kernel has a remote memory corruption vulnerability
that can be remotely triggered by loading the ip_nat_snmp_basic
module and traffic is network-translated on port 161 or 162.
Szymon Zygmunt and Michal Bartoszkiewicz discovered a memory alignment
error in libgadu (from ekg, console Gadu Gadu client, an instant
messaging program) which is included in gaim, a multi-protocol instant
messaging client, as well. This can not be exploited on the x86
architecture but on others, e.g. on Sparc and lead to a bus error,
in other words a denial of service.
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.
libpam-ldap, the PAM LDAP interface, has a vulnerability in which
it fails to authenticate with an LDAP server which is not configured
properly, allowing an authentication bypass.
A heap based buffer overflow bug was found in the way libpng strips alpha
channels from a PNG image. An attacker could create a carefully crafted PNG
image file in such a way that it could cause an application linked with
libpng to crash or execute arbitrary code when the file is opened by a
victim.
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.
An arbitrary command execute bug was found in the lynx "lynxcgi:" URI
handler. An attacker could create a web page redirecting to a malicious URL
which could execute arbitrary code as the user running lynx.
Mailman 2.1.5 and below have a denial of service vulnerability
in the Scrubber.py script. If a maliciously created message
with a mime multi part format is received, mailman delivery
can be stopped.
MySQL 5.0.18 and earlier allows local users to bypass logging mechanisms
via SQL queries that contain the NULL character, which are not properly
handled by the mysql_real_query function. NOTE: this issue was originally
reported for the mysql_query function, but the vendor states that since
mysql_query expects a null character, this is not an issue for mysql_query.
Stefano Di Paola discovered an information leak in the login packet
parser. By sending a specially crafted malformed login packet, a
remote attacker could exploit this to read a random piece of memory,
which could potentially reveal sensitive data. (CVE-2006-1516)
Stefano Di Paola also found a similar information leak in the parser
for the COM_TABLE_DUMP request. (CVE-2006-1517)
Kurt Fitzner discovered that the NBD (network block device) server did not
correctly verify the maximum size of request packets. By sending specially
crafted large request packets, a remote attacker who is allowed to access
the server could exploit this to execute arbitrary code with root
privileges.
When starting xntpd with the -u option and specifying the
group by using a string not a numeric gid the daemon uses
the gid of the user not the group. This problem is now fixed
by this update.
The libUil component of the OpenMotif toolkit has a pair of buffer
overflow vulnerabilities that can possibly be used for the execution
of arbitrary code.
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.
The php wordwrap() function is vulnerable to an integer overflow.
Attackers can submit long arguments to cause a heap-based buffer
overflow, allowing arbitrary code execution.
PHP 5.x and PHP 4.4.2 have a problem with the substr_compare() function.
An attacker can use an out-of-bounds offset argument to cause a
memory access violation, causing a denial of service.
A bug in zend_hash_del() allowed attackers to prevent unsetting of some variables
It was discovered that phpbb2, a web based bulletin board, insufficiently
sanitizes values passed to the "Font Color 3" setting, which might lead to
the execution of injected code by admin users.
The phpbb2 web forum has a number of vulnerabilities including:
a web script injection problem, a protection mechanism bypass, a
security check bypass, a remote global variable bypass, cross site
scripting vulnerabilities, an SQL injection vulnerability,
a remote regular expression modification problem, missing input
sanitizing, and a missing request validation problem.
Stefan Esser reported multiple vulnerabilities
found in phpMyAdmin. The $GLOBALS variable allows modifying the global
variable import_blacklist to open phpMyAdmin to local and remote file
inclusion, depending on your PHP version (CVE-2005-4079, PMASA-2005-9).
Furthermore, it is also possible to conduct an XSS attack via the
$HTTP_HOST variable and a local and remote file inclusion because the
contents of the variable are under total control of the attacker
(CVE-2005-3665, PMASA-2005-8).
The PostgreSQL team has put out a set of "urgent updates" (in the form of the 7.3.15, 7.4.13, 8.0.8, and 8.1.4 releases) closing a
newly-discovered set of SQL injection issues. Details about the problem
can be found on the
technical information page; in short: multi-byte encodings can be used
to defeat normal string sanitizing techniques. The update fixes one problem
related to invalid multi-byte characters, but punts on another by simply
disallowing the old, unsafe technique of escaping single quotes with a
backslash.
HTTP requests with conflicting Content-Length and Transfer-Encoding headers
could lead to HTTP Request Smuggling Attack, which can be exploited to
bypass packet filters or poison web caches.
Py2Play uses Python pickles to send objects over a peer-to-peer game network, that clients accept without restriction the objects and code sent by peers. A remote attacker participating in a Py2Play-powered game can send
malicious Python pickles, resulting in the execution of arbitrary
Python code on the targeted game client.
Paul Jakma discovered that Quagga's ripd daemon did not properly
handle authentication of RIPv1 requests. If the RIPv1 protocol had
been disabled, or authentication for RIPv2 had been enabled, ripd
still replied to RIPv1 requests, which could lead to information
disclosure. (CVE-2006-2223)
Paul Jakma also noticed that ripd accepted unauthenticated RIPv1
response packets if RIPv2 was configured to require authentication and
both protocols were allowed. A remote attacker could exploit this to
inject arbitrary routes. (CVE-2006-2224)
Fredrik Widell discovered that Quagga did not properly handle certain
invalid 'sh ip bgp' commands. By sending special commands to Quagga, a
remote attacker with telnet access to the Quagga server could exploit
this to trigger an endless loop in the daemon (Denial of Service).
(CVE-2006-2276)
Luigi Auriemma discovered multiple flaws in the Scorched 3D game
server, including a format string vulnerability and several buffer
overflows. A remote attacker could exploit these vulnerabilities to crash
a game server or execute arbitrary code with the rights of the game server
user.
The useradd tool from the shadow-utils package has a potential security
problem. When a new user's mailbox is created, the permissions are
set to random garbage from the stack, potentially allowing the
file to be read or written during the time before fchmod() is called.
A vulnerability has been discovered in SpamAssassin, a Perl-based spam
filter using text analysis, that can allow remote attackers to execute
arbitrary commands. This problem only affects systems where spamd is
reachable via the internet and used with vpopmail virtual users, via
the "-v" / "--vpopmail" switch, and with the "-P" / "--paranoid"
switch.
Webmail.php in SquirrelMail 1.4.0 to 1.4.5 allows remote attackers to
inject arbitrary web pages into the right frame via a URL in the
right_frame parameter. NOTE: this has been called a cross-site scripting
(XSS) issue, but it is different than what is normally identified as
XSS. (CVE-2006-0188)
Interpretation conflict in the MagicHTML filter in SquirrelMail 1.4.0 to
1.4.5 allows remote attackers to conduct cross-site scripting (XSS) attacks
via style sheet specifiers with invalid (1) "/*" and "*/" comments, or (2)
a newline in a "url" specifier, which is processed by certain web browsers
including Internet Explorer. (CVE-2006-0195)
CRLF injection vulnerability in SquirrelMail 1.4.0 to 1.4.5 allows remote
attackers to inject arbitrary IMAP commands via newline characters in the
mailbox parameter of the sqimap_mailbox_select command, aka "IMAP
injection." (CVE-2006-0377)
A buffer overflow in UnZip 5.50 and earlier allows local users to execute
arbitrary code via a long filename command line argument. NOTE: since the
overflow occurs in a non-setuid program, there are not many scenarios under
which it poses a vulnerability, unless unzip is passed long arguments when
it is invoked from other programs.
xtensive testing of libwww's handling of multipart/byteranges content from
HTTP/1.1 servers revealed multiple logical flaws and bugs in
Library/src/HTBound.c
xine-lib does an improper input data boundary check on
MPEG streams. A specially crafted MPEG file can be
created that can cause arbitrary code execution when the
file is accessed.
There is a buffer overflow in the Xrender extension of the X.Org server; any process which is able to connect to the server may be able to exploit this overflow to run arbitrary code. Since the X server runs as root on most systems, this vulnerability could be exploited to gain root access. See the X.Org advisory for more information.
A flaw was discovered in Xpdf in that could allow an attacker to construct
a carefully crafted PDF file that would cause Xpdf to consume all available
disk space in /tmp when opened.
xpdf has a number of integer overflows.
A remote attacker can trick a user into opening a maliciously
crafted pdf file, allowing the attacker to execute code with the
privileges of the local user.
This also affects the Poppler library, cupsys and tetex-bin.
Andrea Barisani of Gentoo Linux discovered xzgv and zgv allocate
insufficient memory when rendering images with more than 3 output
components, such as images using the YCCK or CMYK colour space. When
xzgv or zgv attempt to render the image, data from the image overruns a
heap allocated buffer.
