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TITLE:
Microsoft .NET Framework Multiple Vulnerabilities

SECUNIA ADVISORY ID:
SA47323

VERIFY ADVISORY:
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http://secunia.com/advisories/47323/
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https://ca.secunia.com/?page=viewadvisory&vuln_id=47323

RELEASE DATE:
2011-12-29

DISCUSS ADVISORY:
http://secunia.com/advisories/47323/#comments

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http://secunia.com/advisories/47323/

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https://ca.secunia.com/?page=viewadvisory&vuln_id=47323

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DESCRIPTION:
Four vulnerabilities have been reported in Microsoft .NET Framework,
which can be exploited by malicious people to cause a DoS (Denial of
Service), conduct spoofing attacks, or bypass certain security
restrictions.

1) An error within ASP.NET when hashing form posts and updating a
hash table can be exploited to cause a hash collision resulting in
high CPU consumption via a specially crafted form sent in a HTTP POST
request.

Successful exploitation of this vulnerability requires that a site
allows "application/x-www-form-urlencoded" or "multipart/form-data"
HTTP content types.

2) An error in the verification of return URLs during the forms
authentication process can be exploited to redirect a user to an
arbitrary website without the user's knowledge to e.g. conduct
phishing attacks.

Successful exploitation of this vulnerability requires that "Forms
Authentication" is configured per-application to be enabled.

3) An error in the authentication process when handling specially
crafted usernames can be exploited to access arbitrary users'
accounts to an ASP.NET application via a specially crafted web
request.

Successful exploitation of this vulnerability requires that "Forms
Authentication" is configured per-application to be enabled and that
a user can register an account on the ASP.NET application and knows
of a target user's account name.

4) An error in the handling of cached content when "Forms
Authentication" is used with sliding expiry can be exploited to
execute arbitrary commands in context of a target user tricked into
following a specially crafted link.

Successful exploitation of this vulnerability requires that ASP.NET
responses are cached through use of the "OutputCache" directive.

SOLUTION:
Apply patches.

Further details available in Customer Area:
http://secunia.com/vulnerability_intelligence/

PROVIDED AND/OR DISCOVERED BY:
1) Alexander Klink, n.runs AG and Julian Wälde, Technische
Universität Darmstadt.
2-4) Reported by the vendor.

ORIGINAL ADVISORY:
MS11-100 (KB2638420, KB2656351, KB2656352, KB2656353, KB2656355,
KB2656356, KB2656358, KB2656362, KB2657424):
http://technet.microsoft.com/en-us/security/bulletin/MS11-100

n.runs (SA-2011.004):
http://www.nruns.com/_downloads/advisory28122011.pdf

OTHER REFERENCES:
Further details available in Customer Area:
http://secunia.com/vulnerability_intelligence/

DEEP LINKS:
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EXTENDED DESCRIPTION:
Further details available in Customer Area:
http://secunia.com/vulnerability_intelligence/

EXTENDED SOLUTION:
Further details available in Customer Area:
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EXPLOIT:
Further details available in Customer Area:
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About:
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