Date: Mon, 9 Dec 2013 18:39:30 -0500 (EST) From: cve-assign@...re.org To: gmurphy@...hat.com Cc: cve-assign@...re.org, oss-security@...ts.openwall.com Subject: Re: Issue with PYTHON_EGG_CACHE -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 > Python .egg files can be loaded dynamically as dependencies. In order > to process native DSO in .egg distributions the content of the file is > unpacked. By default Python unpacks the files to $HOME/.python-eggs > however this 'egg cache' directory can be overwritten by setting the > environment variable PYTHON_EGG_CACHE. > > It is common practice to set this to a world writeable directory such > as /tmp in the instances where the user the process is executing as > does not have a home directory (e.g. httpd). Unfortunately the > extraction is done in such a way that the extraction path for the DSO > is deterministic. As such it exposes a TOCTOU attack vector where a > user my pre-emptively injecting a specially crafted DSO to achieve > arbitrary code execution and potentially privilege escalation. > > The current version of setuptools attempts to mitigate this threat by > a number of additional integrity checks in conjunction with issuing a > warning if the extract directory is group or world writeable. > > This fix was introduced in version 0.6.46 of Python setuptools > (https://pypi.python.org/pypi/setuptools#id48). This report didn't have enough information to assign any CVE IDs. When you say "It is common practice to set this to a world writeable directory such as /tmp in the instances where the user the process is executing as does not have a home directory (e.g. httpd)," can you describe where this common practice is observed? It seems likely that a separate CVE ID could be assigned for each application that follows this unsafe practice, as long as the application is an open-source product intended for deployment at multiple arbitrary sites. Looking at this from the perspective of setuptools "Issue a warning if the PYTHON_EGG_CACHE or otherwise customized egg cache location specifies a directory that's group- or world-writable," this seems to be a security improvement, not a vulnerability fix. Accordingly, a CVE ID would probably not be assigned with setuptools as the affected/responsible product. - -- 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) iQEcBAEBAgAGBQJSplCSAAoJEKllVAevmvmsQCMIAKY/Z3HKUGt64j/sCCK8QlC8 esrR9EGrGDpL+Rqog+RdARYeFnTjWWf7umKppFu5Pw6rsX+r/Gjg1izh3AZDP+rs y7I+efa7JyOeVSeUd3CecgdEztNiF1Vqg6jrMvvNyix7zpUyAkvz/frJQDgmHv+1 kpdiwBBHDkQhVPR0wLGbna6Yrj4JZuG30/I0Zxp/8cMsGnkfv2NAuqZJQ0C4U2Jv uMA2cHfY8A6Fz+Rm1IhJxxNjkVJ/qgFZVqAlo3E4HfnJTCxTGajHHyRF1oxJIjqu dszkIVYADr542Bd28JT1ARjvEdJzWPLN5BjHC+1T7+HIxUkhkGi6IJV8KL9mdqs= =qxcY -----END PGP SIGNATURE-----
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