oss-sec mailing list archives

Re: openssh on linux rce in sftp-only mode


From: Josh Bressers <bressers () redhat com>
Date: Wed, 8 Oct 2014 15:32:23 -0400 (EDT)


I reported this to the OpenSSH developers, and although they included my
patch as a mitigation, they did not treat it as a vuln in OpenSSH.

I believe that treating this as a hardening patch makes sense. The SFTP
server behaves exactly as documented, it allows access to the whole
filesystem. And on Linux, that happens to equal write access to the
process RAM, so you should never give that access to someone who
shouldn't be able to run arbitrary code.


I think one has to assume if a user has unrestricted sftp access, they can
figure out how to do most anything. Even with the upstream hardening patch,
it really only protects the sftpd process. Any other processes the user may
own could be modified.

I would hesitate to call this a security issue, if we do I think we open a
can of worms.

-- 
    JB


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