Webmin is a web-based system administration console allowing an administrator to easily configure servers and other features. Using the 'buildpkg' FEATURE, or the -b/-B emerge options, Portage can build reusable binary packages for any of the packages available through the Portage tree.
Tavis Ormandy of the Gentoo Linux Security Audit Team discovered that the Webmin ebuild contains a design flaw. It imports the encrypted local root password into the miniserv.users file before building binary packages that include this file.
A remote attacker could retrieve Portage-built Webmin binary packages and recover the encrypted root password from the build host.
Users who never built or shared a Webmin binary package are unaffected by this.
Webmin users should delete any old shared Webmin binary package as soon as possible. They should also consider their buildhost root password potentially exposed and follow proper audit procedures.
If you plan to build binary packages, you should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=app-admin/webmin-1.170-r3"