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Date: Thu, 23 Jan 2014 16:46:54 -0700
From: "Vincent Danen" <>
To: "OSS Security List" <>
Subject: CVE-2014-0022 insecure install of rpm packages via yum cron

Just wanted to give a heads up of a flaw that was reported to our bugzilla.  Our primary bug on this is here:

I'm just going to cut-n-paste what I wrote in the bug.  Obviously no CVE needs to be assigned; this is for others who may be shipping yum.

Gabriel VLASIU reported [1] that yum-cron would install unsigned RPM packages that yum itself would refuse to install.  The yum-cron code is based on that in  This is due to  the installUpdates() function (processPkgs() in failing to fully check the return code of the called sigCheckPkg() function.  sigCheckPkg() is described thus:

    def sigCheckPkg(self, po):
        """Verify the GPG signature of the given package object.

        :param po: the package object to verify the signature of
        :return: (result, error_string)
           where result is::

              0 = GPG signature verifies ok or verification is not required.
              1 = GPG verification failed but installation of the right GPG key
                    might help.
              2 = Fatal GPG verification error, give up.

However, the processPkgs() and installUpdates() calling function do not account for return code 2:

    def processPkgs(self, dlpkgs):
        for po in dlpkgs:
            result, err = self.updd.sigCheckPkg(po)
            if result == 0:
            elif result == 1:
                except yum.Errors.YumBaseError, errmsg:


    def installUpdates(self, emit):
        for po in dlpkgs:
            result, err = self.sigCheckPkg(po)
            if result == 0:
            elif result == 1:
                except yum.Errors.YumBaseError, errmsg:
                    return False replaced in Fedora 19 (3.4.3-47); earlier versions of Fedora use yum-updatesd.

This has been corrected upstream [2] and in Fedora via yum-3.4.3-132.fc19 and yum-3.4.3-130.fc20.

This does not affect Red Hat Enterprise Linux 6 as it used neither yum-updatesd nor yum-cron; it used a shellscript that called yum itself to do updates.


Vincent Danen / Red Hat Security Response Team
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