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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2011.0901 Potential security exposure with IBM HTTP Server 8.0 and earlier 2 September 2011 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: IBM HTTP Server 2.0 IBM HTTP Server 6.0 IBM HTTP Server 6.1 IBM HTTP Server 7.0 IBM HTTP Server 8.0 Publisher: IBM Operating System: AIX HP-UX Linux variants Solaris Windows Impact/Access: Denial of Service -- Remote/Unauthenticated Resolution: Patch/Upgrade CVE Names: CVE-2011-3192 Reference: ESB-2011.0896 ESB-2011.0887 ESB-2011.0881 ESB-2011.0870.2 Original Bulletin: http://www-01.ibm.com/support/docview.wss?uid=swg21512087 - --------------------------BEGIN INCLUDED TEXT-------------------- Potential security exposure with IBM HTTP Server 8.0 and earlier (PM46234) (CVE-2011-3192) Flash (Alert) Document information IBM HTTP Server Software version: 2.0, 6.0, 6.1, 7.0, 8.0 Operating system(s): AIX, HP-UX, IBM i, Linux, Solaris, Windows, i5/OS, z/OS Software edition: All Editions Reference #: 1512087 Modified date: 2011-09-01 Abstract Crafted range requests can result in potential denial of service with IBM HTTP Server (IHS). Content Versions affected: Affected: IBM HTTP Server (IHS) Versions 2.0 (2.0.42 and 2.0.47), 6.0 through 6.0.2.43, 6.1 through 6.1.0.39, 7.0 through 7.0.0.17, and 8.0 are affected. All WebSphere Application Server product Versions, using these affected IHS versions, are affected. All WebSphere Application Server Hypervisors, using these affected IHS versions, are affected. IBM HTTP Server for z/OS (powered by Apache) Versions 6.1, 7.0 and 8.0 are affected. Not Affected: IBM HTTP Server Version 1.3.x is not affected. However, due to issues in the handling of its range requests, we strongly recommend upgrading to an in-service Version of IBM HTTP Server. Version 1.3.26 is no longer is service (ended September 2006). Version 1.3.28 is no longer is service (ended September 2008). IBM HTTP Server for z/OS Version 530 is not affected. Problem Description: Potential denial of service from attack using crafted range requests (CVE Reference: CVE-2011-3192). Circumvention/Solution: Note: Circumvention may be applied to affected WebSphere Application Server and Websphere Application Server Hypervisor environments. For Circumvention: For IBM HTTP Server for all operating systems: For IBM HTTP Server 7.0 and later: This workaround treats requests for 25 or more ranges as requests for the entire file. Make sure mod_headers and mod_setenvif are loaded/uncommented. Append the following to the bottom of httpd.conf: SetEnvIf Range (?:,.*?){25,25} bad-range=1 RequestHeader unset Range env=bad-range # We always drop Request-Range; as this is a legacy # dating back to MSIE3 and Netscape 2 and 3. RequestHeader unset Request-Range # optional logging. CustomLog logs/range-CVE-2011-3192.log common env=bad-range For IBM HTTP Server 6.1, 6.0, and 2.0.47: Two workarounds are available, implementing one is sufficient. Option 1: The first option ignores all Range requests and returns the full page instead (the HTTP RFC says servers may simply ignore Range requests). Make sure mod_headers is loaded/uncommented. Append the following to the bottom of httpd.conf: RequestHeader unset Range RequestHeader unset Request-Range Option 2: This alternative workaround rejects requests with 25 or more ranges and should only be used if the above has a negative impact. Make sure mod_rewrite and mod_headers is loaded/uncommented. Add the following to the bottom of httpd.conf (but before any other RewriteRule directives) and to the top of each <VirtualHost> stanza (before any other RewriteRule directives): # Reject request when more than 25 ranges in the Range: header. # CVE-2011-3192 # RewriteEngine on RewriteCond %{HTTP:Range} (?:,[^,]+){25} [NC] RewriteRule .* - [F] # We always drop Request-Range; as this is a legacy # dating back to MSIE3 and Netscape 2 and 3. RequestHeader unset Request-Range Note: All ifixes and their respective availability dates are listed below. Please check back here for the ifixes at the posted projected availability dates. For Long-Term Solution (ifixes): Applying Interim Fix APAR PM46234, or a Fix Pack containing this APAR, resolves this issue. For IBM HTTP Server for distributed operating systems: For Version 8.0: Apply Interim Fix APAR PM46234 (projected to be available 9 September 2011). --OR-- Apply Fix Pack 1, or later (8.0.0.1) (projected to be available 26 September 2011). For Versions 7.0 and 7.0.0.19: Apply Fix Pack 17 or Fix Pack 19 (7.0.0.17 or 7.0.0.19) (Fix Pack 19 is projected to be available 12 September 2011) , if not already at that level, then Apply Interim Fix APAR PM46234 (Interim Fix APAR for 7.0.0.17 projected to be available 2 September 2011). (Interim Fix APAR for 7.0.0.19 projected to be available 12 September 2011). --OR-- Apply Fix Pack 21, or later (7.0.0.21) (projected to be available 1 September 2011). For Versions 6.1 through 6.1.0.39: Apply Fix Pack 39 (6.1.0.39), if not already at that level, then Apply Interim Fix APAR PM46234 (projected to be available 1 September 2011). --OR-- Apply Fix Pack 41, or later (6.1.0.41) (projected to be available 17 November 2011). For Versions 6.0 through 6.0.2.42: Apply Fix Pack 43 (6.0.2.43), if not already at that level, then Apply Interim Fix APAR PM46234 (projected to be available 7 September 2011). Note: IBM HTTP Server Version 6.0.x was provided with WebSphere Application Server Version 6.0, which is no longer in service (ended September 2010). Additional assistance will only be provided if you have a support extension contract in place, or with the purchase of a support extension contract. For Versions 2.0 (2.0.42 and 2.0.47): Contact IBM Technical Support for a PM46234 cumulative ifix (projected to be available 16 September 2011). IBM HTTP Version 2.0.42 was provided with WebSphere Application Server Version 5.0, and IBM HTTP Server Version 2.0.47 was provided with WebSphere Application Server Version 5.1. WebSphere App Server Version 5.0 is no longer in service (ended September 2006). WebSphere App Server Version 5.1 is no longer in service (ended September 2008). Additional assistance will only be provided if you have a support extension contract in place, or with the purchase of a support extension contract. For IBM HTTP Server for z/OS (powered by Apache): For V8.0.0.0: Apply APAR PM46234 by way of the appropriate Cumulative APAR (Fix Pack) for 8.0.0.1, or later (targeted to be available September 2011). For V7.0.0.0 through 7.0.0.18: Apply APAR PM46234 by way of the appropriate Cumulative APAR (Fix Pack) for 7.0.0.19, or later (targeted to be available September 2011). For V6.1.0.0 through 6.1.0.39: Apply APAR PM46234 by way of the appropriate Cumulative APAR (Fix Pack) for 6.1.0.41, or later (targeted to be available November 2011). Note: Customers may chose to follow the directions "For Circumvention" as a temporary solution, or while waiting for the Cumulative APAR containing this solution. For IBM WebSphere Application Server Hypervisor Edition: For Version 7.0: This fix will be embedded into IBM WebSphere Application Server Hypervisor Edition version 7.0.0.21 (projected to be available Jan 2012) For versions prior to 7.0.0.21, please follow the directions for 'IBM HTTP Server Versions 7.0 and 7.0.0.19' For Version 6.1: This fix will be embedded into IBM WebSphere Application Server Hypervisor Edition version 6.1.0.41 (projected to be available Nov 2011) For versions prior to 6.1.0.41, please follow the directions for 'IBM HTTP Server Versions 6.1 and 6.1.0.39' Note: Since it takes several weeks after a Fix Pack is released before a refreshed WebSphere Application Server Hypervisor Edition virtual image becomes available, customers may choose to apply the IBM HTTP Server Fix Pack or Interim Fix listed in the Long-Term Solution section "For IBM HTTP Server for distributed operating systems" directly within their running instances rather than waiting for the updated virtual image. 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On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iQIVAwUBTmBBnu4yVqjM2NGpAQLECRAAt9C+Nim/474Y4EluNROQrHqjbGgQOmbK WLzJs6Lwhmapkg9uSt/McjnLAOmA1k+LjenO0FRJmHoVQiGq3h9Y9nV0eWTp9p/+ h4pg1B40jpgh8NTEnR2HioyNuFcZCK0xISOYHinU4/RTb5ohwl/I4L589PTcb7bw 1TEw9vVvad7J6PJwXmXnw2s5kYgrF63371GjD6hotrbUPzebLkvSURA0gcNjKB8b ZcP7sB0G/7tzNwfRpCX/Ldc2xlEX2YOjOLIdSFTEEQk4sHAFkd6A6HjDVXEbJwch DFnfNeKomHO8GdEhEHrsHJq4Zycj/2CiN0IVmOLwpmPSR/OzL2iRmm8cKDGGZK6Y zOFWhqjyPt5JpXdDNEWTmr3qbLHoma8dd0I/TseyOuBuYxucab+Ah0u11wYTRVDA 2aVl3Nml1qG7BeGfEuYJrumBMCc20b6fTAa5Esr3jhtWCFUvtfJVKbdWCw3R79jU zdR35rsYrhYccOpVwRwWYZtz74luP9a8gElhTzGs8Ei9pJLHnB16bE/umf46tw8t 6P7koMfBBhEmWiBZ2izfznvw+WTz6WXQOFUBXI2ZSkVEjCzKLiRk7FruMrtR6VRM i2ivCIfPCnoszm8mos7yxONX93cENISWy0CfJ1qg0Uo0iAS3TD1ueGBzzABeG51C h22YcI2Pllg= =oSnq -----END PGP SIGNATURE-----