Thanks!
I found out my mistake.

In My rule there was <regex>Password Last Set: \d</regex>. The sign "+" 
after "\d" was absent.

When I pasted your <regex>Password Last Set: \d+</regex> the rule works 
perfectly.

So I wonder, why my rule didn't work? Or where can I find explanation of 
regular expressions of Ossec?


On Wednesday, August 8, 2012 6:21:54 PM UTC+4, dan (ddpbsd) wrote:
>
> On Wed, Aug 8, 2012 at 10:11 AM, Dmitry <[email protected] <javascript:>> 
> wrote: 
> > You see the rule 18111 is "A user account was changed" 
> > In the part of log "Changed Attributes" there are all the names of 
> > attributes and there is only one value of changed attribute. 
> > So in any alert of rule 18111 there is the name of attribute "Password 
> Last 
> > Set" 
> > 
> > So the only way to determine the change of password is to look for a 
> digit 
> > after "Password Last Set: ". 
> > In other case there will be "-" 
> > 
>
> <rule id="100089" level="7"> 
>   <if_sid>18111</if_sid> 
>   <regex>Password Last Set: \d+</regex> 
>   <description>blahblah</description> 
> </rule> 
>
>
> # cat /tmp/p 
> WinEvtLog: Security: AUDIT_SUCCESS(4738): 
> Microsoft-Windows-Security-Auditing: (no user): no domain: 
> SRV-DC.ft.local: A user account was changed. Subject: Security ID: 
> S-1-5-21-3227760434-1372198118-1359596449-1114 Account Name: dg 
> Account Domain: FL Logon ID: 0x1204753c Target Account: Security ID: 
> S-1-5-21-3227760434-1372198118-1359596449-1269 Account Name: DP 
> Account Domain: FL Changed Attributes: SAM Account Name: - Display 
> Name: - User Principal Name: - Home Directory: - Home Drive: - Script 
> Path: - Profile Path: - User Workstations: - Password Last Set: 
> 8/8/2012 2:42:44 PM Account Expires: - Primary Group ID: - 
> AllowedToDelegateTo: - Old UAC Value: - New UAC Value: - User Account 
> Control: - User Parameters: - SID History: - Logon Hours: - Additional 
> Information: Privileges: - 
> # cat /tmp/p | /var/ossec/bin/ossec-logtest 
> 2012/08/08 10:20:52 ossec-testrule: INFO: Reading decoder file 
> etc/decoder.xml. 
> 2012/08/08 10:20:52 ossec-testrule: INFO: Reading decoder file 
> etc/local_decoder.xml. 
> 2012/08/08 10:20:52 ossec-testrule: INFO: Reading decoder file 
> etc/wip/nsd_decoder.xml. 
> 2012/08/08 10:20:52 ossec-testrule: INFO: Reading loading the lists 
> file: 'lists/blocked.txt.cdb' 
> 2012/08/08 10:20:52 ossec-testrule: INFO: Reading loading the lists 
> file: 'lists/userlist.txt.cdb' 
> 2012/08/08 10:20:52 ossec-testrule: INFO: Reading loading the lists 
> file: 'lists/banneduser.txt.cdb' 
> 2012/08/08 10:20:53 ossec-testrule: INFO: Started (pid: 26728). 
> ossec-testrule: Type one log per line. 
>
>
>
> **Phase 1: Completed pre-decoding. 
>        full event: 'WinEvtLog: Security: AUDIT_SUCCESS(4738): 
> Microsoft-Windows-Security-Auditing: (no user): no domain: 
> SRV-DC.ft.local: A user account was changed. Subject: Security ID: 
> S-1-5-21-3227760434-1372198118-1359596449-1114 Account Name: dg 
> Account Domain: FL Logon ID: 0x1204753c Target Account: Security ID: 
> S-1-5-21-3227760434-1372198118-1359596449-1269 Account Name: DP 
> Account Domain: FL Changed Attributes: SAM Account Name: - Display 
> Name: - User Principal Name: - Home Directory: - Home Drive: - Script 
> Path: - Profile Path: - User Workstations: - Password Last Set: 
> 8/8/2012 2:42:44 PM Account Expires: - Primary Group ID: - 
> AllowedToDelegateTo: - Old UAC Value: - New UAC Value: - User Account 
> Control: - User Parameters: - SID History: - Logon Hours: - Additional 
> Information: Privileges: -' 
>        hostname: 'ix' 
>        program_name: '(null)' 
>        log: 'WinEvtLog: Security: AUDIT_SUCCESS(4738): 
> Microsoft-Windows-Security-Auditing: (no user): no domain: 
> SRV-DC.ft.local: A user account was changed. Subject: Security ID: 
> S-1-5-21-3227760434-1372198118-1359596449-1114 Account Name: dg 
> Account Domain: FL Logon ID: 0x1204753c Target Account: Security ID: 
> S-1-5-21-3227760434-1372198118-1359596449-1269 Account Name: DP 
> Account Domain: FL Changed Attributes: SAM Account Name: - Display 
> Name: - User Principal Name: - Home Directory: - Home Drive: - Script 
> Path: - Profile Path: - User Workstations: - Password Last Set: 
> 8/8/2012 2:42:44 PM Account Expires: - Primary Group ID: - 
> AllowedToDelegateTo: - Old UAC Value: - New UAC Value: - User Account 
> Control: - User Parameters: - SID History: - Logon Hours: - Additional 
> Information: Privileges: -' 
>
> **Phase 2: Completed decoding. 
>        decoder: 'windows' 
>        status: 'AUDIT_SUCCESS' 
>        id: '4738' 
>        extra_data: 'Microsoft-Windows-Security-Auditing' 
>        dstuser: '(no user)' 
>        system_name: 'SRV-DC.ft.local' 
>
> **Phase 3: Completed filtering (rules). 
>        Rule id: '100089' 
>        Level: '7' 
>        Description: 'blahblah' 
> **Alert to be generated. 
>
>
>
>
>
> > On Wednesday, August 8, 2012 4:28:10 PM UTC+4, dan (ddpbsd) wrote: 
> >> 
> >> On Wed, Aug 8, 2012 at 7:29 AM, Dmitry <[email protected]> wrote: 
> >> > Hi! 
> >> > 
> >> > In Windows Log event that says about changing password looks like: 
> >> > 
> >> > WinEvtLog: Security: AUDIT_SUCCESS(4738): 
> >> > Microsoft-Windows-Security-Auditing: (no user): no domain: 
> >> > SRV-DC.ft.local: 
> >> > A user account was changed. Subject: Security ID: 
> >> > S-1-5-21-3227760434-1372198118-1359596449-1114 Account Name: dg 
> Account 
> >> > Domain: FL Logon ID: 0x1204753c Target Account: Security ID: 
> >> > S-1-5-21-3227760434-1372198118-1359596449-1269 Account Name: DP 
> Account 
> >> > Domain: FL Changed Attributes: SAM Account Name: - Display Name: - 
> User 
> >> > Principal Name: - Home Directory: - Home Drive: - Script Path: - 
> Profile 
> >> > Path: - User Workstations: - Password Last Set: 8/8/2012 2:42:44 PM 
> >> > Account 
> >> > Expires: - Primary Group ID: - AllowedToDelegateTo: - Old UAC Value: 
> - 
> >> > New 
> >> > UAC Value: - User Account Control: - User Parameters: - SID History: 
> - 
> >> > Logon 
> >> > Hours: - Additional Information: Privileges: - 
> >> > 
> >> > This log triggered alert of rule 18111 (Windows account changed). 
> >> > 
> >> > In order to have separate rule "Password changed" I wrote rule: 
> >> > 
> >> > <!-- Password changed for Windows Account --> 
> >> > <rule id="100003" level="7"> 
> >> > <if_sid>18111</if_sid> 
> >> > <regex>Password Last Set: \d </regex> 
> >> > <description>Password changed for Windows account</description> 
> >> >   </rule> 
> >> > 
> >> > Dut it doesn't work. When I use <match> instead of <regex> it doesn't 
> >> > help. 
> >> > 
> >> > 
> >> 
> >> This works fine for me: 
> >> 
> >> <rule id="100089" level="7"> 
> >>   <if_sid>18111</if_sid> 
> >>   <match>Password Last Set:</match> 
> >>   <description>blahblah</description> 
> >> </rule> 
>

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