First published: Tue Aug 25 2015(Updated: )
The following vulnerability in util-linux was announced (taken from <a href="http://seclists.org/oss-sec/2015/q3/423">http://seclists.org/oss-sec/2015/q3/423</a>): """ If the chfn and chsh binaries (both setuid-root) from util-linux/login-utils are compiled WITHOUT libuser support, they eventually call mkostemp(localtmp, O_RDWR|O_CREAT|O_EXCL|O_CLOEXEC); where localtmp is "/etc/%s.XXXXXX" and %s is __progname (i.e., argv[0]'s basename). An attacker could repeatedly execve chfn as "ld.so" until mkostemp() creates "/etc/ld.so.preload" (after a few days, in our tests). This particular example doesn't actually work, because "preload" is 7 chars and "XXXXXX" is 6 chars, but it seems there are other interesting possibilities, like "/etc/rc.status" and "/etc/krb5.keytab". The impact of this vulnerability is probably very limited: most Linux distributions ship either the chfn/chsh binaries from the shadow-utils (NOT the login-utils ones), or the login-utils ones but WITH libuser support. """ Upstream patch: <a href="https://github.com/karelzak/util-linux/commit/bde91c85bdc77975155058276f99d2e0f5eab5a9">https://github.com/karelzak/util-linux/commit/bde91c85bdc77975155058276f99d2e0f5eab5a9</a>
Credit: secalert@redhat.com
Affected Software | Affected Version | How to fix |
---|---|---|
Kernel Util-linux | <=2.26.2 | |
Kernel Util-linux | =2.27-rc1 |
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