A NULL pointer dereference flaw was discovered in httpd's mod_proxy_ftp module. Malicious FTP server can use this flaw to crash httpd's child process via malformed reply to EPSV FTP command. Problem was confirmed in both 2.0.x and 2.2.x httpd versions. References: http://www.intevydis.com/blog/?p=59 http://secunia.com/advisories/36549/
Note: The impact of this flaw is rather limited. Using a default prefork MPM (Multi-Processing Module), this casues a crash of a httpd child process. As with prefork MPM, only one request is served by each child process at any time, the problem only breaks current request and does not causes denial of service for whole daemon or other concurrent requests served by other child processes. When multi-threaded worker MPM is used (not default on Red Hat Enterprise Linux or Fedora), crash of a child process can break other concurrent requests served by the same child process at the moment of the crash. Additionally, httpd's proxying is typically used as reverse proxy, rather than forward proxy, where servers to which requests are proxied are trusted, and hence no trust boundary is crossed in such setups.
This problem is not limited to EPSV command reply. Similar problem exists in handling of PASV command (that code is reached e.g. when FTP server does not implement EPSV).
MITRE's CVE-2009-3094 record: ----------------------------- The ap_proxy_ftp_handler function in modules/proxy/proxy_ftp.c in the mod_proxy_ftp module in the Apache HTTP Server 2.0.63 and 2.2.13 allows remote FTP servers to cause a denial of service (NULL pointer dereference and child process crash) via a malformed reply to an EPSV command. References: ----------- http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-3094 http://intevydis.com/vd-list.shtml http://www.intevydis.com/blog/?p=59 http://secunia.com/advisories/36549
This affects httpd version in Red Hat Enterprise Linux 3, 4, and 5, Red Hat Application Stack v2, JBoss Enterprise Web Server, and upstream versions up to the current 2.2.13. This was rated as having low security impact, future updates may address this flaw. Upstream commit: http://svn.apache.org/viewvc?view=rev&revision=814652
This issue has been addressed in following products: Red Hat Web Application Stack for RHEL 5 Via RHSA-2009:1461 https://rhn.redhat.com/errata/RHSA-2009-1461.html
Issue was fixed in upstream Apache httpd 2.2.14-dev version: http://httpd.apache.org/security/vulnerabilities_22.html
This issue has been addressed in following products: Red Hat Enterprise Linux 4 Via RHSA-2009:1580 https://rhn.redhat.com/errata/RHSA-2009-1580.html
This issue has been addressed in following products: Red Hat Enterprise Linux 5 Red Hat Enterprise Linux 3 Via RHSA-2009:1579 https://rhn.redhat.com/errata/RHSA-2009-1579.html
httpd-2.2.14-1.fc11 has been submitted as an update for Fedora 11. http://admin.fedoraproject.org/updates/httpd-2.2.14-1.fc11
httpd-2.2.14-1.fc10 has been submitted as an update for Fedora 10. http://admin.fedoraproject.org/updates/httpd-2.2.14-1.fc10
httpd-2.2.14-1.fc10 has been pushed to the Fedora 10 stable repository. If problems still persist, please make note of it in this bug report.
httpd-2.2.14-1.fc12 has been pushed to the Fedora 12 stable repository. If problems still persist, please make note of it in this bug report.
This issue has been addressed in following products: JBEWS 1.0.0 for RHEL 4 JBEWS 1.0.0 for RHEL 5 Via RHSA-2010:0011 https://rhn.redhat.com/errata/RHSA-2010-0011.html
httpd-2.2.14-1.fc11 has been pushed to the Fedora 11 stable repository. If problems still persist, please make note of it in this bug report.
This issue has been addressed in following products: Red Hat Certificate System 7.3 Via RHSA-2010:0602 https://rhn.redhat.com/errata/RHSA-2010-0602.html