Package: openssh-client
Version: 1:6.7p1-5
Severity: important
Tags: security
Dear Maintainer,
I believe that the sanest way to generate an SSH fingerprint, for display
to users, etc, is via executing:
ssh-keygen -l -f path/to/public.key
This is the rationale behind the following blog-post:
http://blog.steve.org.uk/generating_fingerprints_from_ssh_keys.html
The gzipped key attached to this email, generated via magical-fuzzing,
will result in a segfault, and a suspicious EIP setting. This may
indicate code-execution possiblities, and so should probably have
a CVE identifier assigned.
Demonstration is as simple as:
helsinki ~ $ ssh-keygen -l -f ~/key.trigger.pub
Segmentation fault
The backtrace shows EIP as 0x000055555556807e, which looks at least
partially controllable. I've not yet delved into the details.
-- System Information:
Debian Release: 8.2
APT prefers stable-updates
APT policy: (500, 'stable-updates'), (500, 'stable')
Architecture: amd64 (x86_64)
Kernel: Linux 3.16.0-4-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.utf8, LC_CTYPE=en_US.utf8 (charmap=UTF-8) (ignored: LC_ALL set to en_US.UTF8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
Versions of packages openssh-client depends on:
ii adduser 3.113+nmu3
ii dpkg 1.17.25
ii libc6 2.19-18+deb8u1
ii libedit2 3.1-20140620-2
ii libgssapi-krb5-2 1.12.1+dfsg-19
ii libselinux1 2.3-2
ii libssl1.0.0 1.0.1k-3+deb8u1
ii passwd 1:4.2-3
ii zlib1g 1:1.2.8.dfsg-2+b1
Versions of packages openssh-client recommends:
ii xauth 1:1.0.9-1
Versions of packages openssh-client suggests:
pn keychain <none>
pn libpam-ssh <none>
pn monkeysphere <none>
pn ssh-askpass <none>
-- Configuration Files:
/etc/ssh/ssh_config changed [not included]
-- no debconf information
Attachment:
key.trigger.pub.gz
Description: application/gzip