Secunia Research: GnuTLS libtasn1 "asn1_find_node()" Buffer Overflow Vulnerabilities

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                    Secunia Research 2017/05/22
					
  GnuTLS libtasn1 "asn1_find_node()" Buffer Overflow Vulnerabilities

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Table of Contents

Affected Software....................................................1
Severity.............................................................2
Description of Vulnerabilities.......................................3
Solution.............................................................4
Time Table...........................................................5
Credits..............................................................6
References...........................................................7
About Flexera Software...............................................8
Verification.........................................................9

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1) Affected Software

* GnuTLS libtasn1 Tiny ASN.1 library 4.x

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2) Severity

Rating: Moderately critical
Impact: System access
Where:  From remote

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3) Description of Vulnerabilities

Secunia Research has discovered multiple vulnerabilities in GnuTLS
libtasn1, which can be exploited by malicious people to compromise
a vulnerable system.

1) Two errors in the "asn1_find_node()" function (lib/parser_aux.c)
can be exploited to cause a stacked-based buffer overflow.

Successful exploitation of the vulnerabilities allows execution
of arbitrary code but requires tricking a user into processing
a specially crafted assignments file by e.g. asn1Coding utility.

The vulnerabilities are confirmed in version 4.10. Other versions
may also be affected.

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4) Solution

Update to version 4.12. Additionally fixed in the GIT repository.

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5) Time Table

2017/05/11 - Initial contact to request security contact.
2017/05/11 - Maintainer responds with security contact.
2017/05/15 - Maintainer provided with the vulnerability details.
2017/05/16 - Communication about the impacts and possible vector.
2017/05/18 - Maintainer provides a patch in the official source
             code repository.
2017/05/22 - Release of Secunia Advisory SA76125.
2017/05/22 - Public disclosure of Secunia Research Advisory.
2017/06/07 - Updated "Solution" section due to a fixed version
             release.

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6) Credits

Discovered by Jakub Jirasek, Secunia Research at Flexera Software.

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7) References

The Flexera Software CNA has assigned the CVE-2017-6891 identifier
for the vulnerabilities through the Common Vulnerabilities and
Exposures (CVE) project.

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8) About Flexera Software

Flexera Software helps application producers and enterprises increase
application usage and the value they derive from their software.

http://www.flexerasoftware.com/enterprise/company/about/

Flexera Software  delivers  market-leading  Software  Vulnerability
Management solutions enabling enterprises to proactively identify and
remediate software vulnerabilities, effectively reducing the risk of
costly security breaches.

http://www.flexerasoftware.com/enterprise/products/

Flexera  Software  supports  and  contributes  to  the community in
several ways.  We have always believed that reliable vulnerability
intelligence and tools to aid identifying and fixing vulnerabilities
should be  freely available  for  consumers  to ensure that users,
who care about their online privacy and security, can stay secure.
Only a few vendors address vulnerabilities in a proper way and help
users get updated  and  stay secure.  End-users (whether private
individuals or businesses) are otherwise left largely alone,  and
that is why back in 2002, Secunia Research started investigating,
coordinating  disclosure  and  verifying software vulnerabilities.
In  2016,  Secunia Research  became  a  part  of  Flexera Software
and today our in-house software vulnerability research remains the
core  of  the  Software  Vulnerability  Management  products  at
Flexera Software.

https://secuniaresearch.flexerasoftware.com/secunia_research/

The  public  Advisory database  contains sufficient information  for
researchers, security enthusiasts, and consumers to lookup individual
products and vulnerabilities  and  assess, whether they need to take
any actions to secure their systems or whether a given vulnerability
has already been discovered

https://secuniaresearch.flexerasoftware.com/advisories/

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9) Verification

Please verify this advisory by visiting the Secunia website:
https://secuniaresearch.flexerasoftware.com/secunia_research/2017-11/

Complete list of vulnerability reports published by Secunia Research:
https://secuniaresearch.flexerasoftware.com/secunia_research/

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