Bug 1202410 (CVE-2015-0285) - CVE-2015-0285 openssl: handshake with unseeded PRNG
Summary: CVE-2015-0285 openssl: handshake with unseeded PRNG
Keywords:
Status: CLOSED NOTABUG
Alias: CVE-2015-0285
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
low
low
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard: impact=low,public=20150319,reported=2...
Depends On:
Blocks: 1202442
TreeView+ depends on / blocked
 
Reported: 2015-03-16 14:48 UTC by Martin Prpič
Modified: 2019-06-08 20:29 UTC (History)
47 users (show)

Fixed In Version: openssl 1.0.2a
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2015-03-18 03:38:40 UTC


Attachments (Terms of Use)

Description Martin Prpič 2015-03-16 14:48:46 UTC
Under certain conditions an OpenSSL 1.0.2 client can complete a handshake with an unseeded PRNG. The conditions are:

- The client is on a platform where the PRNG has not been seeded automatically, and the user has not seeded manually

- A protocol specific client method version has been used (i.e. not SSL_client_methodv23)

- A ciphersuite is used that does not require additional random data from the PRNG beyond the initial ClientHello client random (e.g. PSK-RC4-SHA).

If the handshake succeeds then the client random that has been used will have
been generated from a PRNG with insufficient entropy and therefore the output
may be predictable.

For example using the following command with an unseeded openssl will succeed on an unpatched platform:

openssl s_client -psk 1a2b3c4d -tls1_2 -cipher PSK-RC4-SHA

This issue affects OpenSSL version 1.0.2, and is fixed in version 1.0.2a.

Upstream patch:

https://git.openssl.org/gitweb/?p=openssl.git;a=commit;h=e1b568dd2462f7cacf98f3d117936c34e2849a6b

Acknowledgements:

Red Hat would like to thank the OpenSSL project for reporting this issue. Upstream acknowledges Matt Caswell of the OpenSSL development team as the original reporter.

Comment 1 Huzaifa S. Sidhpurwala 2015-03-18 03:37:59 UTC
Statement:

This issue did not affect the versions of openssl as shipped with Red Hat Enterprise Linux 5, 6, and 7.


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