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Old 03-15-2014, 04:59 AM   #1
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Unhappy modsecurity seems to have broken apache2 reverse proxy ubuntu server 12.04

this is the first time I have run into issue like this one. I have a java application setting behind a apache2 using `mod_ajp on 8009`. I have noticed that I could not get the client's IP so I have created another virtual host file and switched to `mod_jk`. I have then disabled the virtual host using `mod_ajp`. So my `mod_jk` has been working fine until I started the security hardening from thefanclub I have applied the method shown on the and I was still fine. This morning I have seen logs in the modsecu_audit.log file :

Action: Intercepted (phase 1)
    Stopwatch: 1394809780952048 3090 (- - -)
    Stopwatch2: 1394809780952048 3090; combined=812, p1=492, p2=0, p3=0, p4=0, p5=253,  sr=143, sw=67, l=0, gc=0
    Response-Body-Transformed: Dechunked
    Producer: ModSecurity for Apache/2.6.3 (; OWASP_CRS/2.2.5.
    Server: Apache
    WebApp-Info: "default" "C35A8A3AB916218E923E5A8E6A73595B" ""


On the virtualhost error.log I have the errors below

    [Thu Mar 13 11:18:43 2014] [error] [client] client denied by server  configuration: 
    [Thu Mar 13 11:18:44 2014] [error] [client] ModSecurity: Access denied  with code 403 (phase 2). String match "HTTP/1.1" at REQUEST_PROTOCOL. [file   "/etc/modsecurity/owasp-crs/activated_rules/modsecurity_crs_20_protocol_violations.conf"]  [line "220"] [id "960020"] [rev "2.2.5"] [msg "Pragma Header requires Cache-Control Header  for HTTP/1.1 requests."] [severity "NOTICE"] [tag "RULE_MATURITY/5"] [tag  "RULE_ACCURACY/7"] [tag ""]  [tag "PROTOCOL_VIOLATION/INVALID_HREQ"] [tag ""] [hostname ""] [uri "/"] [unique_id "UyGUFAqzjt0AADfWBbEAAAAA"]
    [Thu Mar 13 11:23:52 2014] [error] [client] ModSecurity: Access denied with code 403 (phase 2). Operator EQ matched 0 at REQUEST_HEADERS. [file "/etc/modsecurity/owasp-crs/activated_rules/modsecurity_crs_21_protocol_anomalies.conf"] [line "47"] [id "960015"] [rev "2.2.5"] [msg "Request Missing an Accept Header"] [severity "CRITICAL"] [tag "PROTOCOL_VIOLATION/MISSING_HEADER_ACCEPT"] [tag "WASCTC/WASC-21"] [tag "OWASP_TOP_10/A7"]  [tag "PCI/6.5.10"] [hostname ""] [uri "/"] [unique_id "UyGVSAqzjt0AADfWBbIAAAAH"]

On the main apache error.log I have:

[Fri Mar 14 15:07:11 2014] [error] [client] ModSecurity: Access denied with code 403 (phase 1). Match of "streq %{SESSION.IP_HASH}" against "TX:ip_hash" 
     required. [file "/etc/modsecurity/owasp-crs/activated_rules/modsecurity_crs_16_session_hijacking.conf"] [line "35"] [id "981059"] [msg "Warning -  Sticky SessionID Data 
     Changed - IP Address Mismatch."] [hostname ""] [uri "/"] [unique_id  "UyMbH8QokBEAAH5mFvgAAAAB"]
     [Fri Mar 14 15:09:35 2014] [notice] SIGUSR1 received.  Doing graceful restart
     [Fri Mar 14 15:09:36 2014] [notice] Apache/2.2.22 (Ubuntu) mod_ssl/2.2.22 OpenSSL/1.0.1 mod_jk/1.2.32 configured -- resuming normal operations
     [Fri Mar 14 15:09:40 2014] [error] [client] ModSecurity: Access denied with code 403 (phase 1). Match of "streq %{SESSION.IP_HASH}" against "TX:ip_hash" 
     required. [file "/etc/modsecurity/owasp-crs/activated_rules/modsecurity_crs_16_session_hijacking.conf"] [line "35"] [id "981059"] [msg "Warning - Sticky SessionID Data 
      Changed - IP Address Mismatch."] [hostname ""] [uri "/"] [unique_id "UyMbtMQokBEAAH7dJ3sAAACB"
I have disabled modsecurity but it now shows the default index page "it works". I have even reactivated the known working virtualhost using `mod_ajp` and none of them seems to be working anymore.

I understand the page is blocked etc but I can't figure out why the reverse proxy would stop working.

  • Question 1 is this a known issue or misconfiguration?
  • Question 2 how do I get the virtual host back up? quick fix would be
removing modsecurity(even though I do not see the correlation).

All suggestions are welcomed . Thanks
Old 04-06-2014, 10:43 PM   #2
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Like any kind of security firewall it will only allow what you tell it to. I think your first destination should be the modsecurity reference manual to learn how to configure it.
Old 04-12-2014, 05:29 AM   #3
Registered: Jan 2007
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Hello Thanks,

Definitely it's a mod_security issue. Will have a look at the reference.


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