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Re: [cross-project-issues-dev] Security changes to SSH and shells explained

Out of curiosity, do you track trusted ip networks per user or
independently from any user?


On 11-09-28 10:56 AM, Denis Roy wrote:
Now that some of the dust has settled on the recent security issues, I
thought it might be good to provide a bit more insight into what your
evil webmasters have done, and what they have planned, in an effort to
maintain high levels of security.

*What are you so afraid of?*
My biggest fear is that someone obtains root access on our servers,
potentially exposing our binary downloads, source code, code signing
certificate, SSL certificates, private information of committers, users
and member organizations, and more.

*_Why strip everyone's shell access?_
*Local shell access is the easiest way to install software that exploits
vulnerabilities to obtain root access. Although we trust our committers,
active shell access is, and has always been, our biggest cause for concern.

_Why restrict the shell to and not*
dev| run a patched kernel to support the large number of
groups that many committers belong to, whereas uses
the Novell-shipped kernel, making it easier and faster to deploy a new
kernel on build.

_But I use keys to log in, isn't that safe?_
*Your private key is stored in a file in a standard location on your
computer, and is available to any piece of software (and malware) that
is running as your user account. If someone obtains a committer's
private key, they can log in to our servers unchallenged and undetected,
where they may have full shell access for weeks, months or years.

_So how will you keep our Shell-Enabled accounts safe from key (or
password) theft?_
*A simple mechanism is now tracking the IP networks from which shell
accounts are used on Soon, when we're confident it
has sufficiently learned your login patterns, that mechanism will
*block* a successful login from an unknown network.**An email will be
sent out to you, and the simple act of responding to that email will
place the unknown network in the trusted list for all.

If the trusted network is not used by anyone for more than two months,
it is no longer trusted.

This mechanism only applies to committers with *full shell access*
logging into * only*. SCM operations occurring on
dev| will not be subjected to this scrutiny since there
is no shell access on those servers.

/Typical use case I:/
While on vacation in the Bahamas, David Williams is committing from a
hotel lobby. Although David has a full shell, his commits are
unchallenged on After successfully opening an SSH shell
on build, he is instantly kicked out and notified via email. After
replying to the email, his subsequent logins succeed. Weeks later, back
in the USA, David receives an unexpected notification that his account
was used successfully from a computer in Spain. He then realizes he
should not have left his computer unattended while ordering that last
margarita in the Bahamas, and proceeds to inform webmaster that his
private key has been compromised.

The would-be hacker in Spain is left with a closed SSH session, and can
no longer connect to any server.
//Typical use case II:/
While at EclipseCon Europe, an elite group of hackers posing as Obeo
committers proceed to distract the webmaster with endless praise and
numerous free drinks, and use his laptop. Although none of the impostors
speak French, the webmaster is unaware that his private key is now
compromised. The next day, the webmaster awakens to a headache and email
notifications that usage of his account has been blocked. A compromise
is avoided, and the impostors frustratingly return empty handed.

*We estimate this mechanism will cause very minimal inconvenience to
you, while offering us excellent protection against private key and
password theft.

Thanks for reading. If you have any questions or concerns, please
contact Matt and I at webmaster@xxxxxxxxxxx.

*Denis Roy*

EclipseCon Europe 2011 <>

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