Apache httpd allows remote attackers to read secret data from process memory if the Limit directive can be set in a users .htaccess file, or if httpd.conf has certain misconfigurations, aka Optionsbleed. This affects the Apache HTTP Server through 2.2.34 and 2.4.x through 2.4.27. The attacker sends an unauthenticated OPTIONS HTTP request when attempting to read secret data. This is a use-after-free issue and thus secret data is not always sent, and the specific data depends on many factors including configuration. Exploitation with .htaccess can be blocked with a patch to the ap_limit_section function in server/core.c.
Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Http_server | Apache | * | 2.2.34 (including) |
| Http_server | Apache | 2.4.0 (including) | 2.4.0 (including) |
| Http_server | Apache | 2.4.1 (including) | 2.4.1 (including) |
| Http_server | Apache | 2.4.2 (including) | 2.4.2 (including) |
| Http_server | Apache | 2.4.3 (including) | 2.4.3 (including) |
| Http_server | Apache | 2.4.4 (including) | 2.4.4 (including) |
| Http_server | Apache | 2.4.6 (including) | 2.4.6 (including) |
| Http_server | Apache | 2.4.7 (including) | 2.4.7 (including) |
| Http_server | Apache | 2.4.9 (including) | 2.4.9 (including) |
| Http_server | Apache | 2.4.10 (including) | 2.4.10 (including) |
| Http_server | Apache | 2.4.12 (including) | 2.4.12 (including) |
| Http_server | Apache | 2.4.16 (including) | 2.4.16 (including) |
| Http_server | Apache | 2.4.17 (including) | 2.4.17 (including) |
| Http_server | Apache | 2.4.18 (including) | 2.4.18 (including) |
| Http_server | Apache | 2.4.20 (including) | 2.4.20 (including) |
| Http_server | Apache | 2.4.23 (including) | 2.4.23 (including) |
| Http_server | Apache | 2.4.25 (including) | 2.4.25 (including) |
| Http_server | Apache | 2.4.26 (including) | 2.4.26 (including) |
| Http_server | Apache | 2.4.27 (including) | 2.4.27 (including) |
| JBoss Core Services on RHEL 6 | RedHat | jbcs-httpd24-httpd-0:2.4.23-125.jbcs.el6 | * |
| JBoss Core Services on RHEL 6 | RedHat | jbcs-httpd24-mod_bmx-0:0.9.6-15.GA.jbcs.el6 | * |
| JBoss Core Services on RHEL 6 | RedHat | jbcs-httpd24-mod_cluster-native-0:1.3.8-1.Final_redhat_1.jbcs.el6 | * |
| JBoss Core Services on RHEL 7 | RedHat | jbcs-httpd24-httpd-0:2.4.23-125.jbcs.el7 | * |
| JBoss Core Services on RHEL 7 | RedHat | jbcs-httpd24-mod_bmx-0:0.9.6-15.GA.jbcs.el7 | * |
| JBoss Core Services on RHEL 7 | RedHat | jbcs-httpd24-mod_cluster-native-0:1.3.8-1.Final_redhat_1.jbcs.el7 | * |
| Red Hat Enterprise Linux 6 | RedHat | httpd-0:2.2.15-60.el6_9.6 | * |
| Red Hat Enterprise Linux 6.7 Extended Update Support | RedHat | httpd-0:2.2.15-47.el6_7.5 | * |
| Red Hat Enterprise Linux 7 | RedHat | httpd-0:2.4.6-67.el7_4.5 | * |
| Red Hat Enterprise Linux 7.2 Extended Update Support | RedHat | httpd-0:2.4.6-40.el7_2.6 | * |
| Red Hat Enterprise Linux 7.3 Extended Update Support | RedHat | httpd-0:2.4.6-45.el7_3.5 | * |
| Red Hat JBoss Core Services 1 | RedHat | httpd | * |
| Red Hat JBoss Enterprise Application Platform 6.4 | RedHat | httpd | * |
| Red Hat JBoss Enterprise Application Platform 6.4 for RHEL 6 | RedHat | httpd-0:2.2.26-57.ep6.el6 | * |
| Red Hat JBoss Enterprise Application Platform 6.4 for RHEL 6 | RedHat | jbcs-httpd24-openssl-1:1.0.2h-14.jbcs.el6 | * |
| Red Hat JBoss Enterprise Application Platform 6.4 for RHEL 6 | RedHat | mod_cluster-native-0:1.2.13-9.Final_redhat_2.ep6.el6 | * |
| Red Hat JBoss Enterprise Application Platform 6.4 for RHEL 7 | RedHat | httpd22-0:2.2.26-58.ep6.el7 | * |
| Red Hat JBoss Enterprise Application Platform 6.4 for RHEL 7 | RedHat | jbcs-httpd24-openssl-1:1.0.2h-14.jbcs.el7 | * |
| Red Hat JBoss Enterprise Application Platform 6.4 for RHEL 7 | RedHat | mod_cluster-native-0:1.2.13-9.Final_redhat_2.ep6.el7 | * |
| Red Hat JBoss Enterprise Web Server 2 for RHEL 6 | RedHat | httpd-0:2.2.26-57.ep6.el6 | * |
| Red Hat JBoss Enterprise Web Server 2 for RHEL 6 | RedHat | jbcs-httpd24-openssl-1:1.0.2h-14.jbcs.el6 | * |
| Red Hat JBoss Enterprise Web Server 2 for RHEL 6 | RedHat | mod_cluster-native-0:1.2.13-9.Final_redhat_2.ep6.el6 | * |
| Red Hat JBoss Enterprise Web Server 2 for RHEL 6 | RedHat | tomcat6-0:6.0.41-19_patch_04.ep6.el6 | * |
| Red Hat JBoss Enterprise Web Server 2 for RHEL 6 | RedHat | tomcat7-0:7.0.54-28_patch_05.ep6.el6 | * |
| Red Hat JBoss Enterprise Web Server 2 for RHEL 7 | RedHat | httpd22-0:2.2.26-58.ep6.el7 | * |
| Red Hat JBoss Enterprise Web Server 2 for RHEL 7 | RedHat | jbcs-httpd24-openssl-1:1.0.2h-14.jbcs.el7 | * |
| Red Hat JBoss Enterprise Web Server 2 for RHEL 7 | RedHat | mod_cluster-native-0:1.2.13-9.Final_redhat_2.ep6.el7 | * |
| Red Hat JBoss Enterprise Web Server 2 for RHEL 7 | RedHat | tomcat6-0:6.0.41-19_patch_04.ep6.el7 | * |
| Red Hat JBoss Enterprise Web Server 2 for RHEL 7 | RedHat | tomcat7-0:7.0.54-28_patch_05.ep6.el7 | * |
| Red Hat JBoss Web Server 2.1 | RedHat | httpd | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 6 | RedHat | httpd24-0:1.1-18.el6 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 6 | RedHat | httpd24-httpd-0:2.4.27-8.el6 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 6.7 EUS | RedHat | httpd24-0:1.1-18.el6 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 6.7 EUS | RedHat | httpd24-httpd-0:2.4.27-8.el6 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | RedHat | httpd24-0:1.1-18.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | RedHat | httpd24-curl-0:7.47.1-4.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | RedHat | httpd24-httpd-0:2.4.27-8.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | RedHat | httpd24-mod_auth_kerb-0:5.4-33.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7 | RedHat | httpd24-nghttp2-0:1.7.1-6.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.3 EUS | RedHat | httpd24-0:1.1-18.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.3 EUS | RedHat | httpd24-curl-0:7.47.1-4.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.3 EUS | RedHat | httpd24-httpd-0:2.4.27-8.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.3 EUS | RedHat | httpd24-mod_auth_kerb-0:5.4-33.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.3 EUS | RedHat | httpd24-nghttp2-0:1.7.1-6.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS | RedHat | httpd24-0:1.1-18.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS | RedHat | httpd24-curl-0:7.47.1-4.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS | RedHat | httpd24-httpd-0:2.4.27-8.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS | RedHat | httpd24-mod_auth_kerb-0:5.4-33.el7 | * |
| Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS | RedHat | httpd24-nghttp2-0:1.7.1-6.el7 | * |
| Apache2 | Ubuntu | artful | * |
| Apache2 | Ubuntu | devel | * |
| Apache2 | Ubuntu | trusty | * |
| Apache2 | Ubuntu | xenial | * |
| Apache2 | Ubuntu | zesty | * |
The use of previously-freed memory can have any number of adverse consequences, ranging from the corruption of valid data to the execution of arbitrary code, depending on the instantiation and timing of the flaw. The simplest way data corruption may occur involves the system’s reuse of the freed memory. Use-after-free errors have two common and sometimes overlapping causes:
In this scenario, the memory in question is allocated to another pointer validly at some point after it has been freed. The original pointer to the freed memory is used again and points to somewhere within the new allocation. As the data is changed, it corrupts the validly used memory; this induces undefined behavior in the process. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.