Security
OpenSSH and keystroke timings
Theoretical security weaknesses have a tendency to move from the realm of theory to that of practice over time. Sometimes it is the result of more compute power being applied or better algorithms being developed, but a weakness is certainly not going to get stronger. So when Kevin Neff started discussing fixing a weakness in OpenSSH on the openbsd-misc mailing list, the folks writing it off as "theoretical" may have been jumping the gun.
When it is in interactive mode—a user typing into a terminal session for example—ssh sends each key pressed by the user in a separate packet. By observing the timing between packets, an observer may be able to determine something about what was typed just by using traffic analysis, without attempting to break the encryption. Researchers found that the inter-packet timing correlated well with the inter-keystroke timing, so that using statistical techniques they were able to reduce the search space for cracking a password by a factor of 50.
This weakness was outlined in a 2001 paper entitled Timing analysis of keystrokes and timing attacks on SSH" [PDF] which looked specifically at the timing-based attack:
The paper looked at the now-deprecated SSH1 protocol, which led some to conclude that it substantially invalidated the weakness. Damien Miller pointed out that it was likely to still be valid:
Pointing at the paper and discounting it because it is ssh1 only is sticking your head in the sand. It is usually easier to research attacks on simpler protocols and work up to more complicated ones later.
There is a fair amount of information that can be gleaned just by looking at the traffic generated over an encrypted session, especially if the attacker can gather a sizable amount of it. There are fairly clear patterns in interactive sessions that can be extracted and used alongside the inter-keystroke timing information to potentially garner lots of useful information. Darrin Chandler describes it this way:
Overall, the reception to making OpenSSH less susceptible to this kind of analysis was positive. It is clearly a difficult attack to mount, logistically if nothing else, but it is not impossible either. Better timing information or analysis techniques might make it easier over time as well and that is enough of a reason to look at ways to fix it.
Brief items
NoScript 1.8.1 and LWN logins
We have received several reports of readers being unable to log in to LWN.net this morning. It appears to be related to upgrading the NoScript Firefox plugin to version 1.8.1. A new feature, called "Automatic Secure Cookie Management", appears to interact badly with LWN's login code. Some workarounds are described in the FAQ. We apologize for any inconvenience.
Update: Peter Palfrader reports that whitelisting lwn.net for "unsafe" https cookies in NoScript Options -> Advanced - HTTPS -> Cookies -> Enable Automatic Secure Cookies Management fixes the issue.
New vulnerabilities
apache2: cross-site scripting
| Package(s): | apache2 | CVE #(s): | CVE-2008-2939 | ||||||||||||||||||||||||||||||||
| Created: | September 15, 2008 | Updated: | December 5, 2008 | ||||||||||||||||||||||||||||||||
| Description: | From the Mandriva advisory: A cross-site scripting vulnerability was found in the mod_proxy_ftp module in Apache that allowed remote attackers to inject arbitrary web script or HTML via wildcards in a pathname in an FTP URI (CVE-2008-2939). | ||||||||||||||||||||||||||||||||||
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ipa: remote password exposure
| Package(s): | ipa | CVE #(s): | CVE-2008-3274 | ||||||||||||
| Created: | September 11, 2008 | Updated: | September 17, 2008 | ||||||||||||
| Description: | From the Red Hat alert: A flaw was found in the Red Hat Enterprise IPA installation procedure. The master Kerberos password was set up in the LDAP server in such a way that it was possible to retrieve the password via an anonymous LDAP connection. | ||||||||||||||
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kernel: integer overflow
| Package(s): | kernel | CVE #(s): | CVE-2008-3276 | ||||||||||||||||||||||||||||||||
| Created: | September 11, 2008 | Updated: | November 5, 2008 | ||||||||||||||||||||||||||||||||
| Description: | From the SUSE alert: An integer overflow flaw was found in the Linux kernel dccp_setsockopt_change() function. An attacker may leverage this vulnerability to trigger a kernel panic on a victim's machine remotely. | ||||||||||||||||||||||||||||||||||
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kernel: multiple vulnerabilities
| Package(s): | linux-2.6.24 | CVE #(s): | CVE-2008-3526 CVE-2008-3534 CVE-2008-3535 CVE-2008-3792 CVE-2008-3915 | ||||||||||||||||||||
| Created: | September 12, 2008 | Updated: | November 3, 2008 | ||||||||||||||||||||
| Description: | From the Debian advisory:
CVE-2008-3526: Eugene Teo reported a missing bounds check in the SCTP subsystem. By exploiting an integer overflow in the SCTP_AUTH_KEY handling code, remote attackers may be able to cause a denial of service in the form of a kernel panic. CVE-2008-3534: Kel Modderman reported an issue in the tmpfs filesystem that allows local users to crash a system by triggering a kernel BUG() assertion. CVE-2008-3535: Alexey Dobriyan discovered an off-by-one-error in the iov_iter_advance function which can be exploited by local users to crash a system, resulting in a denial of service. CVE-2008-3792: Vlad Yasevich reported several NULL pointer reference conditions in the SCTP subsystem that can be triggered by entering sctp-auth codepaths when the AUTH feature is inactive. This may allow attackers to cause a denial of service condition via a system panic. CVE-2008-3915: Johann Dahm and David Richter reported and issue in the nfsd subsystem that may allow remote attackers to cause a denial of service via a buffer overflow. | ||||||||||||||||||||||
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kolab-server: password disclosure
| Package(s): | kolab-server | CVE #(s): | |||||
| Created: | September 15, 2008 | Updated: | September 17, 2008 | ||||
| Description: | From the Mandriva advisory: Gavin McCullagh of Griffith College Dublin reported an issue in Kolab v1 where user passwords were being recorded in the Apache log files due to Kolab using HTTP GET requests rather than HTTP POST requests. This would allow any users with access to the Apache log files to harvest user passwords and possibly other sensitive data. | ||||||
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libxml2: denial of service
| Package(s): | libxml2 | CVE #(s): | CVE-2003-1564 | ||||||||||||||||
| Created: | September 11, 2008 | Updated: | December 4, 2009 | ||||||||||||||||
| Description: | From the Red Hat alert: A denial of service flaw was found in the way libxml2 processed certain content. If an application linked against libxml2 processed malformed XML content, it could cause the application to use an excessive amount of CPU time and memory, and stop responding. | ||||||||||||||||||
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libxml2: buffer overflow
| Package(s): | libxml2 | CVE #(s): | CVE-2008-3529 | ||||||||||||||||||||||||||||||||||||||||
| Created: | September 11, 2008 | Updated: | August 11, 2009 | ||||||||||||||||||||||||||||||||||||||||
| Description: | From the Red Hat alert: A heap-based buffer overflow flaw was found in the way libxml2 handled long XML entity names. If an application linked against libxml2 processed untrusted malformed XML content, it could cause the application to crash or, possibly, execute arbitrary code. | ||||||||||||||||||||||||||||||||||||||||||
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openssh: denial of service
| Package(s): | openssh | CVE #(s): | CVE-2008-4109 | ||||||||||||
| Created: | September 17, 2008 | Updated: | October 7, 2008 | ||||||||||||
| Description: | From the Debian advisory: It has been discovered that the signal handler implementing the login timeout in Debian's version of the OpenSSH server uses functions which are not async-signal-safe, leading to a denial of service vulnerability (CVE-2008-4109). The problem was originally corrected in OpenSSH 4.4p1 (CVE-2006-5051), but the patch backported to the version released with etch was incorrect. | ||||||||||||||
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pam_mount: arbitrary mounting of filesystems
| Package(s): | pam_mount | CVE #(s): | |||||||||||||||||
| Created: | September 12, 2008 | Updated: | September 17, 2008 | ||||||||||||||||
| Description: | From the Fedora advisory: A security flaw in the pam_mount's handling of user defined volumes using the 'luserconf' option has been fixed in this update. The vulnerability allowed users to arbitrarily mount filesystems at arbitrary locations. | ||||||||||||||||||
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postfix: denial of service
| Package(s): | postfix | CVE #(s): | CVE-2008-3889 | ||||||||||||||||||||||||||||
| Created: | September 11, 2008 | Updated: | November 4, 2008 | ||||||||||||||||||||||||||||
| Description: | From the Mandriva alert: A vulnerability in Postfix 2.4 and later was discovered, when running on Linux kernel 2.6, where a local user could cause a denial of service due to Postfix leaking the epoll file descriptor when executing non-Postfix commands. | ||||||||||||||||||||||||||||||
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R-base: arbitrary file overwrite
| Package(s): | R-base | CVE #(s): | CVE-2008-3931 | ||||||||
| Created: | September 17, 2008 | Updated: | September 23, 2008 | ||||||||
| Description: | From the Mandriva advisory: A symlink vulnerability was found in the javareconf script in R that allows local users to overwrite arbitrary files (CVE-2008-3931). | ||||||||||
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redhat-ds-base: multiple vulnerabilities
| Package(s): | redhat-ds-base | CVE #(s): | CVE-2008-2930 CVE-2008-3283 | ||||||||||||
| Created: | September 11, 2008 | Updated: | September 17, 2008 | ||||||||||||
| Description: | From the Red Hat alert:
Multiple memory leaks were identified in the Directory Server. An unauthenticated remote attacker could use these flaws to trigger high memory consumption in the Directory Server, possibly causing it to crash or terminate unexpectedly when the server ran out of available memory. (CVE-2008-3283) Ulf Weltman of Hewlett-Packard discovered a flaw in the way Directory Server handled LDAP search requests with patterns. A remote attacker with access to the LDAP service could create a search request that, when the search pattern was matched against specially crafted data records, caused Directory Server to use a large amount of CPU time. Directory Server did not impose time limits on such search requests. In this updated package, Directory Server imposes a configurable limit on the pattern-search query run time, with the default limit set to 30 seconds. (CVE-2008-2930) | ||||||||||||||
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rsh: directory traversal
| Package(s): | rsh | CVE #(s): | CVE-2004-0175 | ||||
| Created: | September 12, 2008 | Updated: | September 17, 2008 | ||||
| Description: | From the CVE entry: Directory traversal vulnerability in scp for OpenSSH before 3.4p1 allows remote malicious servers to overwrite arbitrary files. NOTE: this may be a rediscovery of CVE-2000-0992. | ||||||
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ssmtp: memory contents disclosure
| Package(s): | ssmtp | CVE #(s): | CVE-2008-3962 | ||||||||
| Created: | September 15, 2008 | Updated: | September 17, 2008 | ||||||||
| Description: | From the Red Hat bugzilla: The from_format function in ssmtp.c in ssmtp 2.62, in certain configurations, uses uninitialized memory for the From: field of an e-mail message, which might allow remote attackers to obtain sensitive information (memory contents) in opportunistic circumstances by reading a message. | ||||||||||
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wireshark: multiple vulnerabilties
| Package(s): | wireshark | CVE #(s): | CVE-2008-3146 CVE-2008-3932 CVE-2008-3933 CVE-2008-3934 | ||||||||||||||||||||||||||||||||||||
| Created: | September 12, 2008 | Updated: | January 12, 2009 | ||||||||||||||||||||||||||||||||||||
| Description: | There are multiple buffer overflows in NCP dissector, an infinite loop in the NCP dissector, a crash could be triggered by zlib-compressed packet data, and also a crash via crafted Tektronix .rf5 file. | ||||||||||||||||||||||||||||||||||||||
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wordnet: buffer overflows
| Package(s): | wordnet | CVE #(s): | CVE-2008-3908 | ||||||||
| Created: | September 16, 2008 | Updated: | October 7, 2008 | ||||||||
| Description: | From the CVE entry: Multiple buffer overflows in Princeton WordNet (wn) 3.0 allow context-dependent attackers to execute arbitrary code via (1) a long argument on the command line; a long (2) WNSEARCHDIR, (3) WNHOME, or (4) WNDBVERSION environment variable; or (5) a user-supplied dictionary (aka data file). NOTE: since WordNet itself does not run with special privileges, this issue only crosses privilege boundaries when WordNet is invoked as a third party component. | ||||||||||
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wordpress: SQL column truncation
| Package(s): | wordpress | CVE #(s): | |||||||||
| Created: | September 12, 2008 | Updated: | September 17, 2008 | ||||||||
| Description: | WordPress 2.6.2 has been released to work around problems with SQL Column Truncation and the weakness of mt_rand(). See this advisory for more information. | ||||||||||
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