REDHAT-BUG-1256686: Low severity util-linux util-linux vulnerability
The following vulnerability in util-linux was announced (taken from http://seclists.org/oss-sec/2015/q3/423):
""" If the chfn and chsh binaries (both setuid-root) from util-linux/login-utils are compiled WITHOUT libuser support, they eventually call mkostemp(localtmp, ORDWR|OCREAT|OEXCL|OCLOEXEC); 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: https://github.com/karelzak/util-linux/commit/bde91c85bdc77975155058276f99d2e0f5eab5a9
Affected Software
Event History
Frequently Asked Questions
What is the severity of REDHAT-BUG-1256686?
The severity of REDHAT-BUG-1256686 is considered high due to the potential for privilege escalation.
What software is affected by REDHAT-BUG-1256686?
The affected software by REDHAT-BUG-1256686 is util-linux, specifically the chfn and chsh binaries.
How do I fix REDHAT-BUG-1256686?
To fix REDHAT-BUG-1256686, upgrade util-linux to a version that includes libuser support.
What are the potential impacts of REDHAT-BUG-1256686?
The potential impacts of REDHAT-BUG-1256686 include unauthorized privilege elevation and possible system compromise.
Is REDHAT-BUG-1256686 limited to specific operating systems?
REDHAT-BUG-1256686 primarily affects Linux distributions that utilize the util-linux package.