Centos
最小化 PHP.CGI.Argument.Injection 並進一步強化 Centos 6.4 Web 伺服器
我們有帶有物理防火牆的 Centos 6.4 伺服器。我們不斷看到防火牆檢測到大量 PHP.CGI.Argument.Injection。在伺服器本身上，我們已經完成了基本的 apache 加固，如下所示。我們正在使用fail2ban 和mod_secure。還可以做些什麼來進一步強化伺服器？
httpd.conf
# # This is the main Apache server configuration file. It contains the # configuration directives that give the server its instructions. # See <URL:http://httpd.apache.org/docs/2.2/> for detailed information. # In particular, see # <URL:http://httpd.apache.org/docs/2.2/mod/directives.html> # for a discussion of each configuration directive. # # # Do NOT simply read the instructions in here without understanding # what they do. They're here only as hints or reminders. If you are unsure # consult the online docs. You have been warned. # # The configuration directives are grouped into three basic sections: # 1. Directives that control the operation of the Apache server process as a # whole (the 'global environment'). # 2. Directives that define the parameters of the 'main' or 'default' server, # which responds to requests that aren't handled by a virtual host. # These directives also provide default values for the settings # of all virtual hosts. # 3. Settings for virtual hosts, which allow Web requests to be sent to # different IP addresses or hostnames and have them handled by the # same Apache server process. # # Configuration and logfile names: If the filenames you specify for many # of the server's control files begin with "/" (or "drive:/" for Win32), the # server will use that explicit path. If the filenames do *not* begin # with "/", the value of ServerRoot is prepended -- so "logs/foo.log" # with ServerRoot set to "/etc/httpd" will be interpreted by the # server as "/etc/httpd/logs/foo.log". # ### Section 1: Global Environment # # The directives in this section affect the overall operation of Apache, # such as the number of concurrent requests it can handle or where it # can find its configuration files. # # # Don't give away too much information about all the subcomponents # we are running. Comment out this line if you don't mind remote sites # finding out what major optional modules you are running ServerTokens OS # # ServerRoot: The top of the directory tree under which the server's # configuration, error, and log files are kept. # # NOTE! If you intend to place this on an NFS (or otherwise network) # mounted filesystem then please read the LockFile documentation # (available at <URL:http://httpd.apache.org/docs/2.2/mod/mpm_common.html#lockfile>); # you will save yourself a lot of trouble. # # Do NOT add a slash at the end of the directory path. # ServerRoot "/etc/httpd" # # PidFile: The file in which the server should record its process # identification number when it starts. Note the PIDFILE variable in # /etc/sysconfig/httpd must be set appropriately if this location is # changed. # PidFile run/httpd.pid # # Timeout: The number of seconds before receives and sends time out. # Timeout 60 # # KeepAlive: Whether or not to allow persistent connections (more than # one request per connection). Set to "Off" to deactivate. # KeepAlive Off # # MaxKeepAliveRequests: The maximum number of requests to allow # during a persistent connection. Set to 0 to allow an unlimited amount. # We recommend you leave this number high, for maximum performance. # MaxKeepAliveRequests 100 # # KeepAliveTimeout: Number of seconds to wait for the next request from the # same client on the same connection. # KeepAliveTimeout 15 ## ## Server-Pool Size Regulation (MPM specific) ## # prefork MPM # StartServers: number of server processes to start # MinSpareServers: minimum number of server processes which are kept spare # MaxSpareServers: maximum number of server processes which are kept spare # ServerLimit: maximum value for MaxClients for the lifetime of the server # MaxClients: maximum number of server processes allowed to start # MaxRequestsPerChild: maximum number of requests a server process serves <IfModule prefork.c> StartServers 8 MinSpareServers 5 MaxSpareServers 20 ServerLimit 256 MaxClients 256 MaxRequestsPerChild 4000 </IfModule> # worker MPM # StartServers: initial number of server processes to start # MaxClients: maximum number of simultaneous client connections # MinSpareThreads: minimum number of worker threads which are kept spare # MaxSpareThreads: maximum number of worker threads which are kept spare # ThreadsPerChild: constant number of worker threads in each server process # MaxRequestsPerChild: maximum number of requests a server process serves <IfModule worker.c> StartServers 4 MaxClients 300 MinSpareThreads 25 MaxSpareThreads 75 ThreadsPerChild 25 MaxRequestsPerChild 0 </IfModule> # # Listen: Allows you to bind Apache to specific IP addresses and/or # ports, in addition to the default. See also the <VirtualHost> # directive. # # Change this to Listen on specific IP addresses as shown below to # prevent Apache from glomming onto all bound IP addresses (0.0.0.0) # #Listen 12.34.56.78:80 Listen 80 # # Dynamic Shared Object (DSO) Support # # To be able to use the functionality of a module which was built as a DSO you # have to place corresponding `LoadModule' lines at this location so the # directives contained in it are actually available _before_ they are used. # Statically compiled modules (those listed by `httpd -l') do not need # to be loaded here. # # Example: # LoadModule foo_module modules/mod_foo.so # #LoadModule auth_basic_module modules/mod_auth_basic.so #LoadModule auth_digest_module modules/mod_auth_digest.so #LoadModule authn_file_module modules/mod_authn_file.so #LoadModule authn_alias_module modules/mod_authn_alias.so #LoadModule authn_anon_module modules/mod_authn_anon.so #LoadModule authn_dbm_module modules/mod_authn_dbm.so #LoadModule authn_default_module modules/mod_authn_default.so #LoadModule authz_host_module modules/mod_authz_host.so #LoadModule authz_user_module modules/mod_authz_user.so #LoadModule authz_owner_module modules/mod_authz_owner.so #LoadModule authz_groupfile_module modules/mod_authz_groupfile.so #LoadModule authz_dbm_module modules/mod_authz_dbm.so LoadModule authz_default_module modules/mod_authz_default.so LoadModule ldap_module modules/mod_ldap.so LoadModule authnz_ldap_module modules/mod_authnz_ldap.so LoadModule include_module modules/mod_include.so LoadModule log_config_module modules/mod_log_config.so LoadModule logio_module modules/mod_logio.so LoadModule env_module modules/mod_env.so LoadModule ext_filter_module modules/mod_ext_filter.so LoadModule mime_magic_module modules/mod_mime_magic.so LoadModule expires_module modules/mod_expires.so LoadModule deflate_module modules/mod_deflate.so LoadModule headers_module modules/mod_headers.so LoadModule usertrack_module modules/mod_usertrack.so LoadModule setenvif_module modules/mod_setenvif.so LoadModule mime_module modules/mod_mime.so #LoadModule dav_module modules/mod_dav.so LoadModule status_module modules/mod_status.so LoadModule autoindex_module modules/mod_autoindex.so LoadModule info_module modules/mod_info.so #LoadModule dav_fs_module modules/mod_dav_fs.so LoadModule vhost_alias_module modules/mod_vhost_alias.so #LoadModule negotiation_module modules/mod_negotiation.so LoadModule dir_module modules/mod_dir.so LoadModule actions_module modules/mod_actions.so #LoadModule speling_module modules/mod_speling.so LoadModule userdir_module modules/mod_userdir.so LoadModule alias_module modules/mod_alias.so #LoadModule substitute_module modules/mod_substitute.so LoadModule rewrite_module modules/mod_rewrite.so #LoadModule proxy_module modules/mod_proxy.so #LoadModule proxy_balancer_module modules/mod_proxy_balancer.so #LoadModule proxy_ftp_module modules/mod_proxy_ftp.so #LoadModule proxy_http_module modules/mod_proxy_http.so #LoadModule proxy_ajp_module modules/mod_proxy_ajp.so #LoadModule proxy_connect_module modules/mod_proxy_connect.so LoadModule cache_module modules/mod_cache.so LoadModule suexec_module modules/mod_suexec.so LoadModule disk_cache_module modules/mod_disk_cache.so LoadModule cgi_module modules/mod_cgi.so LoadModule version_module modules/mod_version.so # # The following modules are not loaded by default: # #LoadModule asis_module modules/mod_asis.so #LoadModule authn_dbd_module modules/mod_authn_dbd.so #LoadModule cern_meta_module modules/mod_cern_meta.so #LoadModule cgid_module modules/mod_cgid.so #LoadModule dbd_module modules/mod_dbd.so #LoadModule dumpio_module modules/mod_dumpio.so #LoadModule filter_module modules/mod_filter.so #LoadModule ident_module modules/mod_ident.so #LoadModule log_forensic_module modules/mod_log_forensic.so #LoadModule unique_id_module modules/mod_unique_id.so # # # Load config files from the config directory "/etc/httpd/conf.d". # Include conf.d/*.conf # #ExtendedStatus On # # User apache Group apache # ServerAdmin root@localhost # # If your host doesn't have a registered DNS name, enter its IP address here. # You will have to access it by its address anyway, and this will make # redirections work in a sensible way. #ServerName http://********:80 # ServerName directive. # UseCanonicalName Off # DocumentRoot "/var/www/html" # First, we configure the "default" to be a very restrictive set of # features. # <Directory /> Options FollowSymLinks AllowOverride None </Directory> <Directory "/var/www/html"> # Options -Indexes FollowSymLinks # AllowOverride None # # Controls who can get stuff from this server. # Order allow,deny Allow from all </Directory> # # See also: http://httpd.apache.org/docs/misc/FAQ.html#forbidden # <IfModule mod_userdir.c> # UserDir disabled # #UserDir public_html </IfModule> DirectoryIndex index.html index.html.var # # AccessFileName: The name of the file to look for in each directory # for additional configuration directives. See also the AllowOverride # directive. # AccessFileName .htaccess # # The following lines prevent .htaccess and .htpasswd files from being # viewed by Web clients. # <Files ~ "^\.ht"> Order allow,deny Deny from all Satisfy All </Files> # # TypesConfig describes where the mime.types file (or equivalent) is # to be found. # TypesConfig /etc/mime.types # a good value. If most of your content is binary, such as applications # or images, you may want to use "application/octet-stream" instead to # keep browsers from trying to display binary files as though they are # text. # DefaultType text/plain # contents of the file itself to determine its type. The MIMEMagicFile # directive tells the module where the hint definitions are located. # <IfModule mod_mime_magic.c> # MIMEMagicFile /usr/share/magic.mime MIMEMagicFile conf/magic </IfModule> # nameserver. # HostnameLookups Off # #EnableMMAP off # #EnableSendfile off # ErrorLog logs/error_log LogLevel warn LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" combined LogFormat "%h %l %u %t \"%r\" %>s %b" common LogFormat "%{Referer}i -> %U" referer LogFormat "%{User-agent}i" agent # "combinedio" includes actual counts of actual bytes received (%I) and sent (%O); this # requires the mod_logio module to be loaded. #LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\" %I %O" combinedio # #CustomLog logs/access_log common # # If you would like to have separate agent and referer logfiles, uncomment # the following directives. # #CustomLog logs/referer_log referer #CustomLog logs/agent_log agent CustomLog logs/access_log combined # Set to "EMail" to also include a mailto: link to the ServerAdmin. # Set to one of: On | Off | EMail # ServerSignature Off # We include the /icons/ alias for FancyIndexed directory listings. If you # do not use FancyIndexing, you may comment this out. # Alias /icons/ "/var/www/icons/" <Directory "/var/www/icons"> Options Indexes MultiViews FollowSymLinks AllowOverride None Order allow,deny Allow from all </Directory> # # WebDAV module configuration section. # <IfModule mod_dav_fs.c> # Location of the WebDAV lock database. DAVLockDB /var/lib/dav/lockdb </IfModule> ScriptAlias /cgi-bin/ "/var/www/cgi-bin/" # # "/var/www/cgi-bin" should be changed to whatever your ScriptAliased # CGI directory exists, if you have that configured. # <Directory "/var/www/cgi-bin"> AllowOverride None Options None Order allow,deny Allow from all </Directory> IndexOptions FancyIndexing VersionSort NameWidth=* HTMLTable Charset=UTF-8 AddIconByEncoding (CMP,/icons/compressed.gif) x-compress x-gzip AddIconByType (TXT,/icons/text.gif) text/* AddIconByType (IMG,/icons/image2.gif) image/* AddIconByType (SND,/icons/sound2.gif) audio/* AddIconByType (VID,/icons/movie.gif) video/* AddIcon /icons/binary.gif .bin .exe AddIcon /icons/binhex.gif .hqx AddIcon /icons/tar.gif .tar AddIcon /icons/world2.gif .wrl .wrl.gz .vrml .vrm .iv AddIcon /icons/compressed.gif .Z .z .tgz .gz .zip AddIcon /icons/a.gif .ps .ai .eps AddIcon /icons/layout.gif .html .shtml .htm .pdf AddIcon /icons/text.gif .txt AddIcon /icons/c.gif .c AddIcon /icons/p.gif .pl .py AddIcon /icons/f.gif .for AddIcon /icons/dvi.gif .dvi AddIcon /icons/uuencoded.gif .uu AddIcon /icons/script.gif .conf .sh .shar .csh .ksh .tcl AddIcon /icons/tex.gif .tex AddIcon /icons/bomb.gif core AddIcon /icons/back.gif .. AddIcon /icons/hand.right.gif README AddIcon /icons/folder.gif ^^DIRECTORY^^ AddIcon /icons/blank.gif ^^BLANKICON^^ # # DefaultIcon is which icon to show for files which do not have an icon # explicitly set. # DefaultIcon /icons/unknown.gif # HeaderName is the name of a file which should be prepended to # directory indexes. ReadmeName README.html HeaderName HEADER.html # # IndexIgnore is a set of filenames which directory indexing should ignore # and not include in the listing. Shell-style wildcarding is permitted. # IndexIgnore .??* *~ *# HEADER* README* RCS CVS *,v *,t # * being a certain language than marking it with the wrong # * language! # DefaultLanguage english # Simplified Chinese (zh-CN) - Spanish (es) - Traditional Chinese (zh-TW) # AddLanguage ca .ca AddLanguage cs .cz .cs AddLanguage da .dk AddLanguage de .de AddLanguage el .el AddLanguage en .en AddLanguage eo .eo AddLanguage es .es AddLanguage et .et AddLanguage fr .fr AddLanguage he .he AddLanguage hr .hr AddLanguage it .it AddLanguage ja .ja AddLanguage ko .ko AddLanguage ltz .ltz AddLanguage nl .nl AddLanguage nn .nn AddLanguage no .no AddLanguage pl .po AddLanguage pt .pt AddLanguage pt-BR .pt-br AddLanguage ru .ru AddLanguage sv .sv AddLanguage zh-CN .zh-cn AddLanguage zh-TW .zh-tw LanguagePriority en ca cs da de el eo es et fr he hr it ja ko ltz nl nn no pl pt pt-BR ru sv zh-CN zh-TW ForceLanguagePriority Prefer Fallback AddDefaultCharset UTF-8 # # AddType allows you to add to or override the MIME configuration # file mime.types for specific file types. # #AddType application/x-tar .tgz # # AddEncoding allows you to have certain browsers uncompress # information on the fly. Note: Not all browsers support this. #AddEncoding x-compress .Z #AddEncoding x-gzip .gz .tgz # If the AddEncoding directives above are commented-out, then you # probably should define those extensions to indicate media types: # AddType application/x-compress .Z AddType application/x-gzip .gz .tgz # # MIME-types for downloading Certificates and CRLs # AddType application/x-x509-ca-cert .crt AddType application/x-pkcs7-crl .crl # # AddHandler allows you to map certain file extensions to "handlers": # actions unrelated to filetype. These can be either built into the server # or added with the Action directive (see below) # # To use CGI scripts outside of ScriptAliased directories: # (You will also need to add "ExecCGI" to the "Options" directive.) # #AddHandler cgi-script .cgi # # For files that include their own HTTP headers: # #AddHandler send-as-is asis # # For type maps (negotiated resources): # (This is enabled by default to allow the Apache "It Worked" page # to be distributed in multiple languages.) # AddHandler type-map var # # Filters allow you to process content before it is sent to the client. # # To parse .shtml files for server-side includes (SSI): # (You will also need to add "Includes" to the "Options" directive.) # AddType text/html .shtml AddOutputFilter INCLUDES .shtml # Action lets you define media types that will execute a script whenever # Format: Action media/type /cgi-script/location # Format: Action handler-name /cgi-script/location # # Some examples: #ErrorDocument 500 "The server made a boo boo." #ErrorDocument 404 /missing.html #ErrorDocument 404 "/cgi-bin/missing_handler.pl" #ErrorDocument 402 http://www.example.com/subscription_info.html # # # Putting this all together, we can internationalize error responses. # # We use Alias to redirect any /error/HTTP_<error>.html.var response to # our collection of by-error message multi-language collections. We use # includes to substitute the appropriate text. # # You can modify the messages' appearance without changing any of the # default HTTP_<error>.html.var files by adding the line: # # Alias /error/include/ "/your/include/path/" # # which allows you to create your own set of files by starting with the # /var/www/error/include/ files and # copying them to /your/include/path/, even on a per-VirtualHost basis. # Alias /error/ "/var/www/error/" <IfModule mod_negotiation.c> <IfModule mod_include.c> <Directory "/var/www/error"> AllowOverride None Options IncludesNoExec AddOutputFilter Includes html AddHandler type-map var Order allow,deny Allow from all LanguagePriority en es de fr ForceLanguagePriority Prefer Fallback </Directory> # ErrorDocument 400 /error/HTTP_BAD_REQUEST.html.var # ErrorDocument 401 /error/HTTP_UNAUTHORIZED.html.var # ErrorDocument 403 /error/HTTP_FORBIDDEN.html.var # ErrorDocument 404 /error/HTTP_NOT_FOUND.html.var # ErrorDocument 405 /error/HTTP_METHOD_NOT_ALLOWED.html.var # ErrorDocument 408 /error/HTTP_REQUEST_TIME_OUT.html.var # ErrorDocument 410 /error/HTTP_GONE.html.var # ErrorDocument 411 /error/HTTP_LENGTH_REQUIRED.html.var # ErrorDocument 412 /error/HTTP_PRECONDITION_FAILED.html.var # ErrorDocument 413 /error/HTTP_REQUEST_ENTITY_TOO_LARGE.html.var # ErrorDocument 414 /error/HTTP_REQUEST_URI_TOO_LARGE.html.var # ErrorDocument 415 /error/HTTP_UNSUPPORTED_MEDIA_TYPE.html.var # ErrorDocument 500 /error/HTTP_INTERNAL_SERVER_ERROR.html.var # ErrorDocument 501 /error/HTTP_NOT_IMPLEMENTED.html.var # ErrorDocument 502 /error/HTTP_BAD_GATEWAY.html.var # ErrorDocument 503 /error/HTTP_SERVICE_UNAVAILABLE.html.var # ErrorDocument 506 /error/HTTP_VARIANT_ALSO_VARIES.html.var </IfModule> </IfModule> # # The following directives modify normal HTTP response behavior to # handle known problems with browser implementations. # BrowserMatch "Mozilla/2" nokeepalive BrowserMatch "MSIE 4\.0b2;" nokeepalive downgrade-1.0 force-response-1.0 BrowserMatch "RealPlayer 4\.0" force-response-1.0 BrowserMatch "Java/1\.0" force-response-1.0 BrowserMatch "JDK/1\.0" force-response-1.0 # # The following directive disables redirects on non-GET requests for # a directory that does not include the trailing slash. This fixes a # problem with Microsoft WebFolders which does not appropriately handle # redirects for folders with DAV methods. # Same deal with Apple's DAV filesystem and Gnome VFS support for DAV. # BrowserMatch "Microsoft Data Access Internet Publishing Provider" redirect-carefully BrowserMatch "MS FrontPage" redirect-carefully BrowserMatch "^WebDrive" redirect-carefully BrowserMatch "^WebDAVFS/1.[0123]" redirect-carefully BrowserMatch "^gnome-vfs/1.0" redirect-carefully BrowserMatch "^XML Spy" redirect-carefully BrowserMatch "^Dreamweaver-WebDAV-SCM1" redirect-carefully
滲透測試
在維護可訪問 Internet 的伺服器時，您真的無法逃避自己執行滲透測試（又名滲透測試）的需要。我通常使用以下工具來執行此操作：
OpenVAS 是一個包含多種服務和工具的框架，可提供全面而強大的漏洞掃描和漏洞管理解決方案。（免費/開源）
Nessus 是由 Tenable Network Security 開發的專有綜合漏洞掃描程序。它在非企業環境中免費供個人使用。它的目標是檢測測試系統上的潛在漏洞。
Metasploit Framework 是一種針對遠端目標機器開發和執行漏洞利用程式碼的工具。
NSA 強化指南
在設置 CentOS 系統時，我通常會閱讀本指南。它特定於 RHEL5，但指南中的所有內容都是相關的，應該遵守。它確實專門討論了強化 Apache。
審計
正如您現在所做的那樣，檢查任何異常情況並跟進它們，並確保您了解它們，以便您可以權衡它們是否是您設置的潛在向量。
Eric Romang 的部落格是查找這些漏洞的一個很好的資源。具體來說，這是您注意到的漏洞利用：CVE-2012-1823 PHP CGI Argument Injection Metasploit Demo。您還可以在這兩個數據庫中查找漏洞：
如果用作 CGI 並且版本 <= 5.3.12 或 <= 5.4.2，則 PHP.CGI.Argument.Injection 漏洞利用允許在 PHP 上遠端執行程式碼。
您在防火牆日誌中看到這些行並不意味著您容易受到攻擊，只是外面的某個人認為您可能會受到攻擊。為此，但這只是我的意見，我有幾位專家強烈反對，讓你的伺服器隱藏其版本控制令牌可能會適得其反，因為潛在的利用者會嘗試他們所有的伎倆——你可能容易受到攻擊的那些，以及那些你不是。如果針對 FooScript 的漏洞利用出現，您將無法倖免，因為您沒有宣傳您對 FooScript 的使用。
因此，您可以做的（我想您已經做過）是將 PHP 作為模組執行和/或將其更新為比易受攻擊的版本更高的版本。一旦您不再容易受到攻擊，您可能希望指示防火牆在沒有警告的情況下放棄這種嘗試（當然，您仍然希望收到有關其他嘗試的警告！）。
通常，您可能還想查看一個或多個漏洞掃描程序。
將 PHP 作為模組或 CGI
PHP 可以通過多種方式安裝。作為一個模組 (
mod_php5)，它“存在”在 Apache 程序中，預設情況下具有相同的權限。您可以將其視為“嵌入”在 Apache 中的 PHP 功能，使其“更智能”。妥協mod_php可能意味著妥協 Apache（有補救措施，但仍然存在），因此它的所有網站。作為一個 CGI，它作為一個單獨的程序（幾個單獨的程序）存在，一些人認為它更安全，而另一些人則認為它的性能較低（每次呼叫都必須重新設置整個程序）。FastCGI 處於中間位置，但需要更多配置；它有兩三種口味。配置看起來不錯；但是，您可能想要更改這些值：
KeepAlive On DefaultType text/html EnableMMAP Onmmap’ing 可以在幾乎沒有成本的情況下提高性能。有一些警告，但它們通常不相關（當然，您將檢查這是否是您的情況）：
這種記憶體映射有時會產生性能改進。但在某些環境中，最好禁用記憶體映射以防止出現操作問題：
On some multiprocessor systems, memory-mapping can reduce the performance of the httpd. Deleting or truncating a file while httpd has it memory-mapped can cause httpd to crash with a segmentation fault.禁用 Keep-Alive 可能會緩解某種 (D)DoS - 請參閱安全提示- 但通常最好採取其他措施，例如禁止（就像您已經做的那樣），這使得禁用 Keep-Alives 在很大程度上是多餘的；雖然擁有它們可以提高“好”客戶的性能（也可以釋放資源來處理壞客戶）。
預設的 content-type
text/html並不真正相關，但我覺得沒有理由讓您的普通Web伺服器預設為純文字。