Date: Thu, 1 May 2014 20:52:37 -0400 (EDT) From: cve-assign@...re.org To: geissert@...ian.org Cc: cve-assign@...re.org, oss-security@...ts.openwall.com Subject: Re: CVE request: directory traversal in DSA-2915-1-patched dpkg in Debian squeeze -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 > The recent update of dpkg for CVE-2014-0471 in Debian squeeze actually > introduces a vulnerability in that release This is a somewhat unusual situation from the perspective of CVE assignment. The outcome of 746306 is that C-style filenames aren't accepted. However, we probably can't assign a CVE ID for a root cause of "attempts to support C-style filenames," because supporting those filenames isn't inherently unsafe if an OS vendor is programmatically, or by policy, ensuring that the patch program is one that interacts safely with that support. The updated dpkg in squeeze + patch(1) from squeeze = vulnerable behavior is something that seems to be best categorized as a release engineering problem. Although there are very few cases in which CVE IDs have been assigned for release engineering problems, these problems can be within the scope of CVE, and the current one is. Use CVE-2014-3127 for this issue. In other words, because squeeze's new dpkg program is incompatible, in a security-relevant way, with squeeze's patch program, the two should not have been allowed to exist together within any correctly maintained/supported squeeze environment. However, there is another question that could possibly result in a second CVE ID. On wheezy, there's apparently a security problem in, at least, these two cases: 1. the installed patch program is an older version of patch that's identical to squeeze's supported version of patch. Possibly, this can happen on a correctly maintained/supported Debian system because sometimes a system is in a partially upgraded state. In particular, the vulnerability affects root's use of dpkg, which may be a completely expected activity because the administrator might want to unpack a source package even though an upgrade is unfinished. 2. the patch program in root's path is not something obtained from Debian, e.g., the administrator intentionally decided to install a non-GNU patch program We're not sure what can be done about case 1. The general issue is that, when doing an upgrade of an arbitrary OS, the system might intermittently be in a state in which incompatibility of old-OS-version programs and new-OS-version programs has a major security risk. Maybe the right answer is a policy that nobody is allowed to do anything while an upgrade is in progress. In other words, regular users may not be logged in, and root should only be running the upgrade program and nothing else. ("nothing else" is impractical; realistically, risk is reduced by running as little else as possible.) Case 2 possibly violates the expectations of the concept of a Linux distribution OS or other OS. In other words, the dpkg program requires the patch program, and therefore the administrator must ensure that the patch program (at least, in root's path) is the one provided by the OS vendor. If the administrator decided to install any other patch program, the resulting security problem would typically be considered a site-specific problem and thus outside the scope of CVE. However, a CVE ID could be assigned of any of these is true: - on wheezy, dpkg doesn't have any explicit requirements about the patch program - the dpkg documentation states that a non-GNU patch program can be used if desired - Debian has a general policy that a supported program (such as dpkg) must be robust in the face of non-standard but reasonable site-specific software changes. In other words, if Debian program 1 allows arbitrary code execution in situations where the administrator replaces Debian program 2 with an often-considered-equivalent non-Debian program, this is supposed to be treated as a vulnerability in Debian program 1. - -- CVE assignment team, MITRE CVE Numbering Authority M/S M300 202 Burlington Road, Bedford, MA 01730 USA [ PGP key available through http://cve.mitre.org/cve/request_id.html ] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.14 (SunOS) iQEcBAEBAgAGBQJTYustAAoJEKllVAevmvmswDgIAIhRUCoIuvrHcrVlhEH2aicu 4eacUenhaY1BfLg167t+csxZooZClRzsykhoun36VlrTT9jzLTBHjrSwupwIaNia LvdmEEMgRcig0nPIl0233Jew3vIWXD+BJcQXOyyGPmjOmWWUew6JO+hkuDGg2JTr r3nyNPQafsbdfBWGZ0rnmOqp+gUc+3bgqReVtsogcXvd0yVbKMFdWm1kuOIHeevf ZWdmBdF2cwWyCGk9SAvRVGj15HxFlmmyuQ4u0PN2oxzbLd8cooJGmZnWz/q8X+h7 A4srxRFTqyHceZgWB0cqsXyjY9oiFEqweC+pA1WHozu+2f2D6isBoH1WYjLOA8c= =PQIS -----END PGP SIGNATURE-----
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