Bug 415361 (CVE-2007-5972)

Summary: CVE-2007-5972 krb5: double free in kdb lib
Product: [Other] Security Response Reporter: Tomas Hoger <thoger>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED NOTABUG QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: nalin
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
URL: http://nvd.nist.gov/nvd.cfm?cvename=CVE-2007-5972
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Fixed In Version: Doc Type: Bug Fix
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Last Closed: 2007-12-14 09:42:39 UTC Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description Tomas Hoger 2007-12-07 08:51:55 UTC 
Common Vulnerabilities and Exposures assigned an identifier CVE-2007-5972 to the following vulnerability:

Double-free vulnerability in the krb5_def_store_mkey function in lib/kdb/kdb_default.c in MIT Kerberos 5 (krb5) 1.5 has unknown impact and remote authenticated attack vectors.  NOTE: the free operations occur in code that stores the krb5kdc master key, and thus the attacker must have privileges to store this key.

References:

http://bugs.gentoo.org/show_bug.cgi?id=199211
Comment 1 Mark J. Cox 2007-12-14 09:42:26 UTC 
MIT say 
http://marc.info/?l=full-disclosure&m=119743235325151&w=2

CVE-2007-5972
http://bugs.gentoo.org/show_bug.cgi?id=199211

This bug is a double-free (actually a double-fclose) bug which is not
a vulnerability due to inaccessibility to an attacker.  If the
fwrite() call in krb5_def_store_mkey() (in src/lib/kdb/kdb_default.c)
fails, the file pointer "kf" may have fclose() called on it twice.

   180      if ((fwrite((krb5_pointer) &enctype,
   181                  2, 1, kf) != 1) ||
   182          (fwrite((krb5_pointer) &key->length,
   183                  sizeof(key->length), 1, kf) != 1) ||
   184          (fwrite((krb5_pointer) key->contents,
   185                  sizeof(key->contents[0]), (unsigned) key->length, 
   186                  kf) != key->length)) {
   187          retval = errno;
   188          (void) fclose(kf);
   189      }
   190      if (fclose(kf) == EOF)
   191          retval = errno;

The relevant code stashes a KDC master key.  It is only run by
explicit action of a KDC administrator, who already has all the
privileges that exploiting this bug would gain.  A properly configured
KDC will have no unprivileged users having shell or other login
access; therefore, an unprivileged user cannot cause the fwrite()
failure necessary for triggering this bug.  Also, under normal
conditions, the code is run exactly once in the lifetime of a KDC: at
database creation time.