__________________________________________________________________
Squid Proxy Cache Security Update Advisory SQUID-2005:4
__________________________________________________________________
Advisory ID: SQUID-2005:4
Date: April 23, 2005
Summary: HTTP Request Smuggling Vulnerabilities
Affected versions: Squid 2.5.STABLE7 and earlier
__________________________________________________________________
/Advisories/SQUID-2005_4.txt
__________________________________________________________________
Problem Description:
Squid is susceptible to a class of attacks known as "HTTP Request
Smuggling." These attacks involve sending malformed HTTP requests
that cause Squid and an upstream HTTP agent (origin server or
another proxy) to disagree on the boundary between HTTP requests
on a persistent connection.
For example, if a PUT or POST request contains two Content-Length
headers, one agent may use the first value, while the other agent
uses the second value. If the PUT/POST body contains data that
looks like another HTTP request, the two agents become out-of-sync.
This may lead to cache poisoning.
Other attack vectors include whitespace in HTTP header names and
extra CR characters at the end of header lines.
__________________________________________________________________
Severity:
This problem is serious because it allows an attacker to poison
Squid's cache.
However, the major aspects of this problem is easily fixed by
disabling (at least temporarily) HTTP persistent connections.
Some of these issues is usually minor in nature and Squid will
only warn when encountering them, but if you are in a complex
hierarchy of proxy servers the situation may be worse allowing
bypass of certain access controls or the like. If you want Squid
to be strict about this class of protocol violations and reject
any such requests or responses then set the new
relaxed_header_parser directive to off.
__________________________________________________________________
Collateral Damage:
After closing these vulnerabilities, Squid rejects certain
malformed HTTP requests and responses. Your users may see
failures (error messages) for sites that used to work because
the protocol error was unnoticed by earlier versions of Squid,
and warning messages will be seen in cache.log for even more
sites where Squid can recover unambiguously.
When encountering such sites it is important you work with the
site owner to make their servers comply with the HTTP
specifications. Most of these problems with servers not complying
to the HTTP specifications can not be worked around in a safe
manner.
__________________________________________________________________
Updated Packages:
This bug is fixed by Squid version 2.5.STABLE8.
In addition, an individual patch for this issues can be found in
our patch archive for version Squid-2.5.STABLE7:
/Versions/v2/2.5/bugs/#squid-2.5.STABLE7-header_parsing
If you are using a prepackaged version of Squid then please refer
to the package vendor for availability information on updated
packages.
__________________________________________________________________
Determining if your version is vulnerable:
Squid versions up to, and including, 2.5.STABLE7 are vulnerable.
__________________________________________________________________
Workarounds:
The simplest workaround is to disable HTTP persistent connections.
Add these lines to your squid.conf:
client_persistent_connections off
server_persistent_connections off
This closes most issues relating to Squid and the cache, but not
all forms of the attack in general.
__________________________________________________________________
Contact details for the Squid project:
For installation / upgrade support: Your first point of contact
should be your binary package vendor.
If your install is built from the original Squid sources, then
the squid-users@squid-cache.org mailing list is your primary
support point. (see
for subscription details).
For bug reporting, particularly security related bugs the
squid-bugs@squid-cache.org mailing list is the appropriate forum.
It's a closed list (though anyone can post) and security related
bug reports are treated in confidence until the impact has been
established. For non security related bugs, the squid bugzilla
database should be used .
__________________________________________________________________
Credits:
The vulnerability was reported by Steve Orrin at Watchfire
Their paper on the subject can be found from
http://www.watchfire.com/resources/HTTP-Request-Smuggling.pdf
__________________________________________________________________
Revision history:
2005-04-23 07:15 GMT Initial version
2005-08-03 15:46 GMT Added reference to the published paper
from Watchfire
2010-09-16 07:05 GMT Reference link updates
__________________________________________________________________
END
387 Captain Parks, however, agreed with Mr. Everdail, who trusted him absolutely—if Sandy did not—that it would be wise not to give any person who had been on the yacht during its crossing any chance to get away. Felipa stood leaning listlessly against the post of the ramada, watching them. After a time she went into the adobe and came out with a pair of field-glasses, following the course of the command as it wound along among the foot-hills. The day dragged dully along. She was uneasy about her husband, her nerves were shaken with the coffee and quinine, and she was filled,[Pg 76] moreover, with a vague restlessness. She would have sent for her horse and gone out even in the clouds of dust and the wind like a hot oven, but Landor had forbidden her to leave the post. Death in the tip of a poisoned arrow, at the point of a yucca lance, or from a more merciful bullet of lead, might lurk behind any mesquite bush or gray rock. Chapter 9 "Very well," answered the Deacon a little stiffly, for he was on his guard against cordial strangers. "Deed he was," answered Si. "He and his fathers before him run' this whole neck o' woods accordin' to the big Injun taste, and give the Army o' the United States all they wanted to do. Used to knock all the other Injuns around here about like ten-pins. The Rosses were bosses from the word go." Little Pete had an idea. He wriggled in between, snatched the glasses, and made off with them. Dara looked away. "I have my song," she said. HoME日韩一级特黄高清免费自拍
ENTER NUMBET 0017
tefan9.com.cn
liqu7.net.cn
db69.com.cn
www.xianjinba.com.cn
dizu8.net.cn
qhande.com.cn
www.reador.com.cn
www.daowu1.net.cn
yanyi1.net.cn
apml.com.cn