Bug 1390182 (CVE-2016-1247) - CVE-2016-1247 nginx: Local privilege escalation via log files
Summary: CVE-2016-1247 nginx: Local privilege escalation via log files
Alias: CVE-2016-1247
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
Depends On: 1390183 1390184 1910628
Blocks: 1390186
TreeView+ depends on / blocked
Reported: 2016-10-31 12:22 UTC by Andrej Nemec
Modified: 2021-06-14 16:32 UTC (History)
14 users (show)

Fixed In Version:
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Doc Text:
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.
Clone Of:
Last Closed: 2016-11-15 04:50:18 UTC

Attachments (Terms of Use)

Description Andrej Nemec 2016-10-31 12:22:00 UTC
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 12:24:05 UTC
Created nginx tracking bugs for this issue:

Affects: fedora-all [bug 1390183]
Affects: epel-all [bug 1390184]

Comment 2 Doran Moppert 2016-10-31 23:39:49 UTC
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 23:44:31 UTC
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 2016-11-15 04:48:51 UTC

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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