Bug 1390182 - (CVE-2016-1247) CVE-2016-1247 nginx: Local privilege escalation via log files
CVE-2016-1247 nginx: Local privilege escalation via log files
Product: Security Response
Classification: Other
Component: vulnerability (Show other bugs)
All Linux
low Severity low
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Assigned To: Red Hat Product Security
: Security
Depends On: 1390183 1390184
Blocks: 1390186
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Reported: 2016-10-31 08:22 EDT by Andrej Nemec
Modified: 2016-11-14 23:50 EST (History)
13 users (show)

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A vulnerability was discovered in nginx. An attacker who could already run commands under the nginx user id could use this access to append data to files owned by root, potentially elevating their own privileges to root.
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Last Closed: 2016-11-14 23:50:18 EST
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RHEL 7.3 requirements from Atomic Host:
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Description Andrej Nemec 2016-10-31 08:22:00 EDT
It was reported that the nginx web server packages in Debian suffered from a > privilege escalation vulnerability (www-data to root) due to the way log files > are handled.

Debian bug report:

Comment 1 Andrej Nemec 2016-10-31 08:24:05 EDT
Created nginx tracking bugs for this issue:

Affects: fedora-all [bug 1390183]
Affects: epel-all [bug 1390184]
Comment 2 Doran Moppert 2016-10-31 19:39:49 EDT
Default SELinux policies on RHEL and Fedora protect against this flaw by limiting the files nginx's (uid 0) logging process can write to (httpd_log_t).

Only systems running with `setenforce 0` or running nginx unconfined are vulnerable to privilege escalation.

With SELinux enforcing, it may still be possible for an attacker to redirect nginx's access.log output to another file labelled with httpd_log_t, but the consequences of such an attack are minimal.
Comment 4 Doran Moppert 2016-11-03 19:44:31 EDT
To exploit this flaw, an attacker must first be able to run code under the nginx uid.  This is only possible if the attacker already has administrative privileges, or has used another vulnerability to gain such access.
Comment 5 Doran Moppert 2016-11-14 23:48:51 EST

Red Hat Product Security has rated this issue as having Low security impact. This issue is not currently planned to be addressed in future updates. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.

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