As discussed in my recent article, Eight Ways to Blacklist with Apache’s mod_rewrite, one method of stopping spammers, scrapers, email harvesters, and malicious bots is to blacklist their associated user agents. Apache enables us to target bad user agents by testing the user-agent string against a predefined blacklist of unwanted visitors. Any bot identifying itself as one of the blacklisted agents is immediately and quietly denied access. While this certainly isn’t the most effective method of securing your site against malicious behavior, it may certainly provide another layer of protection.

Even so, there are several things to consider before choosing to implement an extensive user-agent blacklist on your site. First and most importantly is the transient nature of the user agent itself. On most systems, the user-agent variable is easy to change, making it possible for bot owners to use any user-agent name they wish. Once a bad bot makes the rounds, becomes known, and is blacklisted, the bot owner need only modify or change its declared user agent and they’re back in business. User-agent names are constantly invented, spoofed, or otherwise altered in order to operate beneath — or above — the virtual radar. Thus, a user-agent blacklist is a high-maintenance affair, requiring continuous cultivation in order to maintain relevancy and effectiveness.

Performance is another important issue to consider. While a well-maintained user-agent blacklist may average a reasonable number of user agents, blacklists that are simply appended with new names will eventually grow painfully large and ultimately decrease server performance. Then you’re left with a never-ending blacklist of retired user agents that fails to protect your site while slowing things down to a virtual crawl (no pun intended). And despite your best intentions, we both know that taking time for periodic “blacklist maintenance” is a luxury that simply doesn’t exist, at least for most of us.

As if those reasons weren’t enough to persuade you against using an ultimate user-agent blacklist, here is another: the 4G Blacklist. Put simply, the 4G Blacklist is a more effective way to protect your site against a wide variety of spam, exploits, and malicious attacks. Unlike huge lists of banned user agents, the 4G Blacklist requires zero maintenance, consumes fewer resources, and may retain its effectiveness indefinitely. But alas, for those of you who are still determined to get your hands on the latest “ultimate” user-agent blacklist, here you go..

The Ultimate User-Agent Blacklist

As you may recall, the original Ultimate HTAccess Blacklist was released here at Perishable Press a couple of years ago. Then, several months later, I added more bad user agents, compressed the list into single-line format, and released the Ultimate HTAccess Blacklist 2. This list contained over 300 bad bots and was generally well-received by the community, protecting many sites against a plethora of site rippers, grabbers, spammers, harvesters, bad bots, and other online scum. When used as a solid foundation on which to build and cultivate your own user-agent blacklist, the Ultimate HTAccess Blacklist can do wonders to improve overall performance, decrease site maintenance, and reduce server expense.

Now, in this new and improved version of the Ultimate User-Agent Blacklist, I have integrated my recent collection ¹ of actively malicious bad bots to more than quadruple the number of blocked user agents. This new list features a whopping 1211 blacklisted user agents, including three of my own creation ² to be used exclusively for my diabolical and obsessive monitoring purposes (insert maniacal laughter here). Also, as with the second version of the user-agent blacklist, this new version is written in compressed, single-line format to facilitate usability and performance.

So, without further ado, here is the third incarnation of the Ultimate User-Agent Blacklist. Simply copy and paste the following code into the root HTAccess file of your site to enjoy a serious reduction in wasted bandwidth, stolen resources, and comment spam. Remember to backup your stuff before you meddle with things, and always test, test, test whenever implementing HTAccess directives.

# PERISHABLE PRESS ULTIMATE USER-AGENT BLACKLIST

<IfModule mod_rewrite.c>
RewriteEngine on
RewriteCond %{HTTP_USER_AGENT} ^$|\<|\>|\'|\%|\_iRc|\_Works|\@\$x|\<\?|\$x0e|\+select\+|\+union\+|1\,\1\,1\,|2icommerce|3GSE|4all|59\.64\.153\.|88\.0\.106\.|98|85\.17\.|A\_Browser|ABAC|Abont|abot|Accept|Access|Accoo|AceFTP|Acme|ActiveTouristBot|Address|Adopt|adress|adressendeutschland|ADSARobot|agent|ah\-ha|Ahead|AESOP\_com\_SpiderMan|aipbot|Alarm|Albert|Alek|Alexibot|Alligator|AllSubmitter|alma|almaden|ALot|Alpha|aktuelles|Akregat|Amfi|amzn\_assoc|Anal|Anarchie|andit|Anon|AnotherBot|Ansearch|AnswerBus|antivirx|Apexoo|appie|Aqua_Products|Arachmo|archive|arian|ASPSe|ASSORT|aster|Atari|ATHENS|AtHome|Atlocal|Atomic_Email_Hunter|Atomz|Atrop|^attach|attrib|autoemailspider|autohttp|axod|batch|b2w|Back|BackDoorBot|BackStreet|BackWeb|Badass|Baid|Bali|Bandit|Baidu|Barry|BasicHTTP|BatchFTP|bdfetch|beat|Become|Beij|BenchMark|berts|bew|big.brother|Bigfoot|Bilgi|Bison|Bitacle|Biz360|Black|Black.Hole|BlackWidow|bladder.fusion|Blaiz|Blog.Checker|Blogl|BlogPeople|Blogshares.Spiders|Bloodhound|Blow|bmclient|Board|BOI|boitho|Bond|Bookmark.search.tool|boris|Bost|Boston.Project|BotRightHere|Bot.mailto:craftbot@yahoo.com|BotALot|botpaidtoclick|botw|brandwatch|BravoBrian|Brok|Bropwers|Broth|browseabit|BrowseX|Browsezilla|Bruin|bsalsa|Buddy|Build|Built|Bulls|bumblebee|Bunny|Busca|Busi|Buy|bwh3|c\-spider|CafeK|Cafi|camel|Cand|captu|Catch|cd34|Ceg|CFNetwork|cgichk|Cha0s|Chang|chaos|Char|char\(32\,35\)|charlotte|CheeseBot|Chek|CherryPicker|chill|ChinaClaw|CICC|Cisco|Cita|Clam|Claw|Click.Bot|clipping|clshttp|Clush|COAST|ColdFusion|Coll|Comb|commentreader|Compan|contact|Control|contype|Conc|Conv|Copernic|Copi|Copy|Coral|Corn|core-project|cosmos|costa|cr4nk|crank|craft|Crap|Crawler0|Crazy|Cres|cs\-CZ|cuill|Curl|Custo|Cute|CSHttp|Cyber|cyberalert|^DA$|daoBot|DARK|Data|Daten|Daum|dcbot|dcs|Deep|DepS|Detect|Deweb|Diam|Digger|Digimarc|digout4uagent|DIIbot|Dillo|Ding|DISC|discobot|Disp|Ditto|DLC|DnloadMage|DotBot|Doubanbot|Download|Download.Demon|Download.Devil|Download.Wonder|Downloader|drag|DreamPassport|Drec|Drip|dsdl|dsok|DSurf|DTAAgent|DTS|Dual|dumb|DynaWeb|e\-collector|eag|earn|EARTHCOM|EasyDL|ebin|EBM-APPLE|EBrowse|eCatch|echo|ecollector|Edco|edgeio|efp\@gmx\.net|EirGrabber|email|Email.Extractor|EmailCollector|EmailSearch|EmailSiphon|EmailWolf|Emer|empas|Enfi|Enhan|Enterprise\_Search|envolk|erck|EroCr|ESurf|Eval|Evil|Evere|EWH|Exabot|Exact|EXPLOITER|Expre|Extra|ExtractorPro|EyeN|FairAd|Fake|FANG|FAST|fastlwspider|FavOrg|Favorites.Sweeper|Faxo|FDM\_1|FDSE|fetch|FEZhead|Filan|FileHound|find|Firebat|Firefox.2\.0|Firs|Flam|Flash|FlickBot|Flip|fluffy|flunky|focus|Foob|Fooky|Forex|Forum|ForV|Fost|Foto|Foun|Franklin.Locator|freefind|FreshDownload|FrontPage|FSurf|Fuck|Fuer|futile|Fyber|Gais|GalaxyBot|Galbot|Gamespy\_Arcade|GbPl|Gener|geni|Geona|Get|gigabaz|Gira|Ginxbot|gluc|glx.?v|gnome|Go.Zilla|Goldfire|Google.Wireless.Transcoder|Googlebot\-Image|Got\-It|GOFORIT|gonzo|GornKer|GoSearch|^gotit$|gozilla|grab|Grabber|GrabNet|Grub|Grup|Graf|Green.Research|grub|grub\-client|gsa\-cra|GSearch|GT\:\:WWW|GuideBot|guruji|gvfs|Gyps|hack|haha|hailo|Harv|Hatena|Hax|Head|Helm|herit|hgre|hhjhj\@yahoo|Hippo|hloader|HMView|holm|holy|HomePageSearch|HooWWWer|HouxouCrawler|HMSE|HPPrint|htdig|HTTPConnect|httpdown|http.generic|HTTPGet|httplib|HTTPRetriever|HTTrack|human|Huron|hverify|Hybrid|Hyper|ia\_archiver|iaskspi|IBM\_Planetwide|iCCra|ichiro|ID\-Search|IDA|IDBot|IEAuto|IEMPT|iexplore\.exe|iGetter|Ilse|Iltrov|Image|Image.Stripper|Image.Sucker|imagefetch|iimds\_monitor|Incutio|IncyWincy|Indexer|Industry.Program|Indy|InetURL|informant|InfoNav|InfoTekies|Ingelin|Innerpr|Inspect|InstallShield.DigitalWizard|Insuran\.|Intellig|Intelliseek|InterGET|Internet.Ninja|Internet.x|Internet\_Explorer|InternetLinkagent|InternetSeer.com|Intraf|IP2|Ipsel|Iria|IRLbot|Iron33|Irvine|ISC\_Sys|iSilo|ISRCCrawler|ISSpi|IUPUI.Research.Bot|Jady|Jaka|Jam|^Java|java\/|Java\(tm\)|JBH.agent|Jenny|JetB|JetC|jeteye|jiro|JoBo|JOC|jupit|Just|Jyx|Kapere|kash|Kazo|KBee|Kenjin|Kernel|Keywo|KFSW|KKma|Know|kosmix|KRAE|KRetrieve|Krug|ksibot|ksoap|Kum|KWebGet|Lachesis|lanshan|Lapo|larbin|leacher|leech|LeechFTP|LeechGet|leipzig\.de|Lets|Lexi|lftp|Libby|libcrawl|libcurl|libfetch|libghttp|libWeb|libwhisker|libwww|libwww\-FM|libwww\-perl|LightningDownload|likse|Linc|Link|Link.Sleuth|LinkextractorPro|Linkie|LINKS.ARoMATIZED|LinkScan|linktiger|LinkWalker|Lint|List|lmcrawler|LMQ|LNSpiderguy|loader|LocalcomBot|Locu|London|lone|looksmart|loop|Lork|LTH\_|lwp\-request|LWP|lwp-request|lwp-trivial|Mac.Finder|Macintosh\;.I\;.PPC|Mac\_F|magi|Mag\-Net|Magnet|Magp|Mail.Sweeper|main|majest|Mam|Mana|MarcoPolo|mark.blonin|MarkWatch|MaSagool|Mass|Mass.Downloader|Mata|mavi|McBot|Mecha|MCspider|mediapartners|^Memo|MEGAUPLOAD|MetaProducts.Download.Express|Metaspin|Mete|Microsoft.Data.Access|Microsoft.URL|Microsoft\_Internet\_Explorer|MIDo|MIIx|miner|Mira|MIRE|Mirror|Miss|Missauga|Missigua.Locator|Missouri.College.Browse|Mist|Mizz|MJ12|mkdb|mlbot|MLM|MMMoCrawl|MnoG|moge|Moje|Monster|Monza.Browser|Mooz|Moreoverbot|MOT\-MPx220|mothra\/netscan|mouse|MovableType|Mozdex|Mozi\!|^Mozilla$|Mozilla\/1\.22|Mozilla\/22|^Mozilla\/3\.0.\(compatible|Mozilla\/3\.Mozilla\/2\.01|Mozilla\/4\.0\(compatible|Mozilla\/4\.08|Mozilla\/4\.61.\(Macintosh|Mozilla\/5\.0|Mozilla\/7\.0|Mozilla\/8|Mozilla\/9|Mozilla\:|Mozilla\/Firefox|^Mozilla.*Indy|^Mozilla.*NEWT|^Mozilla*MSIECrawler|Mp3Bot|MPF|MRA|MS.FrontPage|MS.?Search|MSFrontPage|MSIE\_6\.0|MSIE6|MSIECrawler|msnbot\-media|msnbot\-Products|MSNPTC|MSProxy|MSRBOT|multithreaddb|musc|MVAC|MWM|My\_age|MyApp|MyDog|MyEng|MyFamilyBot|MyGetRight|MyIE2|mysearch|myurl|NAG|NAMEPROTECT|NASA.Search|nationaldirectory|Naver|Navr|Near|NetAnts|netattache|Netcach|NetCarta|Netcraft|NetCrawl|NetMech|netprospector|NetResearchServer|NetSp|Net.Vampire|netX|NetZ|Neut|newLISP|NewsGatorInbox|NEWT|NEWT.ActiveX|Next|^NG|NICE|nikto|Nimb|Ninja|Ninte|NIPGCrawler|Noga|nogo|Noko|Nomad|Norb|noxtrumbot|NPbot|NuSe|Nutch|Nutex|NWSp|Obje|Ocel|Octo|ODI3|oegp|Offline|Offline.Explorer|Offline.Navigator|OK.Mozilla|omg|Omni|Onfo|onyx|OpaL|OpenBot|Openf|OpenTextSiteCrawler|OpenU|Orac|OrangeBot|Orbit|Oreg|osis|Outf|Owl|P3P|PackRat|PageGrabber|PagmIEDownload|pansci|Papa|Pars|Patw|pavu|Pb2Pb|pcBrow|PEAR|PEER|PECL|pepe|Perl|PerMan|PersonaPilot|Persuader|petit|PHP|PHP.vers|PHPot|Phras|PicaLo|Piff|Pige|pigs|^Ping|Pingd|PingALink|Pipe|Plag|Plant|playstarmusic|Pluck|Pockey|POE\-Com|Poirot|Pomp|Port.Huron|Post|powerset|Preload|press|Privoxy|Probe|Program.Shareware|Progressive.Download|ProPowerBot|prospector|Provider.Protocol.Discover|ProWebWalker|Prowl|Proxy|Prozilla|psbot|PSurf|psycheclone|^puf$|Pulse|Pump|PushSite|PussyCat|PuxaRapido|PycURL|Pyth|PyQ|QuepasaCreep|Query|Quest|QRVA|Qweer|radian|Radiation|Rambler|RAMP|RealDownload|Reap|Recorder|RedCarpet|RedKernel|ReGet|relevantnoise|replacer|Repo|requ|Rese|Retrieve|Rip|Rix|RMA|Roboz|Rogue|Rover|RPT\-HTTP|Rsync|RTG30|.ru\)|ruby|Rufus|Salt|Sample|SAPO|Sauger|savvy|SBIder|SBP|SCAgent|scan|SCEJ\_|Sched|Schizo|Schlong|Schmo|Scout|Scooter|Scorp|ScoutOut|SCrawl|screen|script|SearchExpress|searchhippo|Searchme|searchpreview|searchterms|Second.Street.Research|Security.Kol|Seekbot|Seeker|Sega|Sensis|Sept|Serious|Sezn|Shai|Share|Sharp|Shaz|shell|shelo|Sherl|Shim|Shiretoko|ShopWiki|SickleBot|Simple|Siph|sitecheck|SiteCrawler|SiteSnagger|Site.Sniper|SiteSucker|sitevigil|SiteX|Sleip|Slide|Slurpy.Verifier|Sly|Smag|SmartDownload|Smurf|sna\-|snag|Snake|Snapbot|Snip|Snoop|So\-net|SocSci|sogou|Sohu|solr|sootle|Soso|SpaceBison|Spad|Span|spanner|Speed|Spegla|Sphere|Sphider|spider|SpiderBot|SpiderEngine|SpiderView|Spin|sproose|Spurl|Spyder|Squi|SQ.Webscanner|sqwid|Sqworm|SSM\_Ag|Stack|Stamina|stamp|Stanford|Statbot|State|Steel|Strateg|Stress|Strip|studybot|Style|subot|Suck|Sume|sun4m|Sunrise|SuperBot|SuperBro|Supervi|Surf4Me|SuperHTTP|Surfbot|SurfWalker|Susi|suza|suzu|Sweep|sygol|syncrisis|Systems|Szukacz|Tagger|Tagyu|tAke|Talkro|TALWinHttpClient|tamu|Tandem|Tarantula|tarspider|tBot|TCF|Tcs\/1|TeamSoft|Tecomi|Teleport|Telesoft|Templeton|Tencent|Terrawiz|Test|TexNut|trivial|Turnitin|The.Intraformant|TheNomad|Thomas|TightTwatBot|Timely|Titan|TMCrawler|TMhtload|toCrawl|Todobr|Tongco|topic|Torrent|Track|translate|Traveler|TREEVIEW|True|Tunnel|turing|Turnitin|TutorGig|TV33\_Mercator|Twat|Tweak|Twice|Twisted.PageGetter|Tygo|ubee|UCmore|UdmSearch|UIowaCrawler|Ultraseek|UMBC|unf|UniversalFeedParser|unknown|UPG1|UtilMind|URLBase|URL.Control|URL\_Spider\_Pro|urldispatcher|URLGetFile|urllib|URLSpiderPro|URLy|User\-Agent|UserAgent|USyd|Vacuum|vagabo|Valet|Valid|Vamp|vayala|VB\_|VCI|VERI\~LI|verif|versus|via|Viewer|virtual|visibilitygap|Visual|vobsub|Void|VoilaBot|voyager|vspider|VSyn|w\:PACBHO60|w0000t|W3C|w3m|w3search|walhello|Walker|Wand|WAOL|WAPT|Watch|Wavefire|wbdbot|Weather|web.by.mail|Web.Data.Extractor|Web.Downloader|Web.Ima|Web.Mole|Web.Sucker|Web2Mal|Web2WAP|WebaltBot|WebAuto|WebBandit|Webbot|WebCapture|WebCat|webcraft\@bea|Webclip|webcollage|WebCollector|WebCopier|WebCopy|WebCor|webcrawl|WebDat|WebDav|webdevil|webdownloader|Webdup|WebEMail|WebEMailExtrac|WebEnhancer|WebFetch|WebGo|WebHook|Webinator|WebInd|webitpr|WebFilter|WebFountain|WebLea|Webmaster|WebmasterWorldForumBot|WebMin|WebMirror|webmole|webpic|WebPin|WebPix|WebReaper|WebRipper|WebRobot|WebSauger|WebSite|Website.eXtractor|Website.Quester|WebSnake|webspider|Webster|WebStripper|websucker|WebTre|WebVac|webwalk|WebWasher|WebWeasel|WebWhacker|WebZIP|Wells|WEP\_S|WEP.Search.00|WeRelateBot|wget|Whack|Whacker|whiz|WhosTalking|Widow|Win67|window.location|Windows.95\;|Windows.95\)|Windows.98\;|Windows.98\)|Winodws|Wildsoft.Surfer|WinHT|winhttp|WinHttpRequest|WinHTTrack|Winnie.Poh|wire|WISEbot|wisenutbot|wish|Wizz|WordP|Works|world|WUMPUS|Wweb|WWWC|WWWOFFLE|WWW\-Collector|WWW.Mechanize|www.ranks.nl|wwwster|^x$|X12R1|x\-Tractor|Xaldon|Xenu|XGET|xirq|Y\!OASIS|Y\!Tunnel|yacy|YaDirectBot|Yahoo\-MMAudVid|YahooSeeker|YahooYSMcm|Yamm|Yand|yang|Yeti|Yoono|yori|Yotta|YTunnel|Zade|zagre|ZBot|Zeal|ZeBot|zerx|Zeus|ZIPCode|Zixy|zmao|Zyborg [NC]
RewriteRule ^(.*)$ - [F,L]
</IfModule>

And, for those of you who enjoy looking at long lists of bad robots, here is the same blacklist of 1211 banned user agents in uncompressed format:

Click image for full-size uncompressed view of 1211 blocked user-agents

I love this game :)

Notes

• ¹ Special thanks to “Mr. M” for graciously sharing his extensive user-agent list and granting permission to integrate them into this version of the blacklist. Thanks M! :)
• ² Free iPod Nano plus honorable mention in my next article for the first person to identify my three “imaginary” (i.e., fake) user agents. Good luck! ;)

Related articles

• 4G Series: The Ultimate Referrer Blacklist, Featuring Over 8000 Banned Referrers
• 2010 User-Agent Blacklist
• Building the 3G Blacklist, Part 3: Improving Site Security by Selectively Blocking Rogue User Agents
• Series Summary: Building the 3G Blacklist
• Ultimate htaccess Blacklist 2 (Compressed Version)
• Ultimate htaccess Blacklist
• Blacklist Candidate Series Summary