oss-sec mailing list archives

Re: CVE Request: reseed


From: Josh Bressers <bressers () redhat com>
Date: Tue, 12 Jul 2011 14:57:20 -0400 (EDT)

----- Original Message -----
On Wed, 2011-07-06 at 07:47 -0500, Jamie Strandboge wrote:
A security bug was reported by Jeffrey Walton against reseed in
Ubuntu. You are being emailed as the upstream contact. Please keep
oss-security () lists openwall com[1] CC'd for any updates on this
issue.

This issue should be considered public. A CVE is being requested;
please mention this in any changelogs.

Details from the public bug follow:
https://launchpad.net/bugs/804594

From the reporter:
"reseed(8) performs an insecure HTTP fetch of data from random.org.
The script is automatically executed when installed, and any time the
user chooses to execute. In addition, the reseed man pages do not
mention the data is retrieved over an insecure channel."

As pointed out by the reporter, from the man page: "It is run once
during the installation of the package only". An attacker could perform
a MITM during package installation or whenever the reseed command is
run to provide predictable data for the random number seed.

While the attack is difficult to achieve (need both MITM at time of
package installation AIUI), it seems that this still should get a CVE.


I'll give the HTTP issue CVE-2011-2683.

In all seriousness though, running this on install should probably get an
ID as you can't say you have complete trust in whatever the default random
site is (in this case it's random.org).

It's probably not safe at all honestly. If you don't have entropy, HTTPS
isn't going to be secure either.

I'd rather not start a fight though by assigning a bunch of IDs for
something that is insecure by design. If you wish for more IDs, please let
me know.

Thanks.

-- 
    JB


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