Bug 1029663 (CVE-2013-4559)
| Summary: | CVE-2013-4559 lighttpd: setuid/setgid/setgroups return value check | ||
|---|---|---|---|
| Product: | [Other] Security Response | Reporter: | Kurt Seifried <kseifried> |
| Component: | vulnerability | Assignee: | Red Hat Product Security <security-response-team> |
| Status: | CLOSED UPSTREAM | QA Contact: | |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | unspecified | CC: | ccoleman, dmcphers, jialiu, lmeyer, matthias, mmcgrath |
| Target Milestone: | --- | Keywords: | Security |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2020-05-20 21:15:21 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
| Bug Depends On: | 1029666, 1029667, 1029669 | ||
| Bug Blocks: | |||
Created lighttpd tracking bugs for this issue: Affects: fedora-all [bug 1029666] Created lighttpd tracking bugs for this issue: Affects: epel-all [bug 1029667] This CVE Bugzilla entry is for community support informational purposes only as it does not affect a package in a commercially supported Red Hat product. Refer to the dependent bugs for status of those individual community products. |
Stefan Bühler of the lighthttpd project reports: setuid/setgid/setgroups return values not checked =================================================== Description ------------- Privilege escalation from lighttpd user ("www-data"). This bug was found with the clang static analyzer. Attack scenario ----------------- In certain cases setuid() and similar can fail; if an environment limits the number of processes a user can have, setuid() might fail if the target uid already is at the limit. A user who can execute processes with the same userid (for example by having write access to CGI scripts) could clone() often; in this case a lighttpd restart would end up with lighttpd running as root, and the CGI scripts would run as root too. It could be possible that remote users could trigger many processes too, and trigger a restart using a different bug in lighttpd. Affected versions ------------------- All versions before 1.4.33. Patch ------- See http://download.lighttpd.net/lighttpd/security/lighttpd-1.4.33_fix_setuid.patch Fixed in ---------- 1.4.x: http://redmine.lighttpd.net/projects/lighttpd/repository/revisions/2923 1.4.34: not released yet (http://www.lighttpd.net/) Solutions or workaround ------------------------- Make sure setuid()/setgid()/... can never fail: * don't have any limits, or * disable mod_cgi (perhaps using fcgi-cgi [3] or scgi-cgi [4] as replacement), and run any backends (FastCGI, SCGI, ...) with different users. Privilege separation is always a good idea! Other restrictions could be in place (AppArmor/SELinux), but they usually either always work or never work. References ------------ [1] http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-XXXX (TBD) [2] http://redmine.lighttpd.net/projects/lighttpd/repository/revisions/2923/diff/ [3] http://redmine.lighttpd.net/projects/fcgi-cgi/wiki [4] http://redmine.lighttpd.net/projects/scgi-cgi/wiki GPG signatures ---------------- * http://download.lighttpd.net/lighttpd/security/lighttpd-1.4.33_fix_setuid.patch.asc * http://download.lighttpd.net/lighttpd/security/lighttpd_sa_2013_02.txt.asc