Anonymize data samples

Anonymize data samples

Splunk contains an anonymize function. The anonymizer combs through sample log files or event files to replace identifying data - usernames, IP addresses, domain names, etc. - with fictional values that maintain the same word length, and event type. For example, it may turn the string user=billg@microsoft.com into user=carol@adalberto.com. This lets Splunk users share log data without revealing confidential or personal information from their networks.

The anonymized file is written to the same directory as the source file, with ANON- prepended to its filename. For example, /tmp/messages will be anonymized as /tmp/ANON-messages.

You can anonymize files from Splunk's CLI. To use Splunk's CLI, navigate to the $SPLUNK_HOME/bin/ directory and use the ./splunk command. You can also add Splunk to your path and use the splunk command.

Simple method

The easiest way to anonymize a file is with the anonymizer tool's defaults, as shown in the session below. Note that you currently need to have $SPLUNK_HOME/bin as your current working directory; this will be fixed in an incremental release.

From the CLI, type the following:

# ./splunk anonymize [filename]

# cp -p /var/log/messages /tmp
# cd $SPLUNK_HOME/bin
# splunk anonymize /tmp/messages
Getting timestamp from: /opt/paul207/splunk/lib/python2.4/site-packages/splunk/timestamp.config
Processing files: ['/tmp/messages']
Getting named entities
        Processing /tmp/messages
Adding named entities to list of public terms: Set(['secErrStr', 'MD_SB_DISKS', 'TTY', 'target', 'precision ', 'lpj', 'ip', 'pci', 'hard', 'last bus', 'override with idebus', 'SecKeychainFindGenericPassword err', 'vector', 'USER', 'irq ', 'com  user', 'uid'])
        Processing /tmp/messages for terms.
        Calculating replacements for 4672 terms.
===================================================
Wrote dictionary scrubbed terms with replacements to "/tmp/INFO-mapping.txt"
Wrote suggestions for dictionary to "/tmp/INFO-suggestions.txt"
===================================================
Writing out /tmp/ANON-messages
Done.

Advanced method

You can customize the anonymizer by telling it what terms to anonymize, what terms to leave alone, and what terms to use as replacements. The advanced form of the command is shown below.

# ./splunk anonymize [filename] [public_terms] [private_terms] [name_terms] [dictionary] [timestamp_config] [branding]

• filename
  • Default: None
  • Path and name of the file to anonymize.
• public_terms
  • Default: $SPLUNK_HOME/bin/public-terms.txt
  • A list of locally-used words that will not be anonymized if they are in the file. It serves as an appendix to the dictionary file.
  • Here is a sample entry:

2003 2004 2005 2006 abort aborted am apr april aug august auth
authorize authorized authorizing bea certificate class com complete

• private_terms
  • Default: $SPLUNK_HOME/bin/private-terms.txt/
  • A list of words that will be anonymized if found in the file, because they may denote confidential information.
  • Here is a sample entry:

481-51-6234
passw0rd

• name_terms
  • Default: $SPLUNK_HOME/bin/names.txt
  • A global list of common English personal names that Splunk uses to replace anonymized words.
  • Splunk always replaces a word with a name of the exact same length, to keep each event's data pattern the same.
  • Splunk uses each name in name_terms once to replace a character string of equal length throughout the file. After it runs out of names, it begins using randomized character strings, but still mapping each replaced pattern to one anonymized string.
  • Here is a sample entry:

charlie
claire
desmond
jack

• dictionary
• Default: $SPLUNK_HOME/bin/dictionary.txt
  • A global list of common words that will not be anonymized, unless overridden by entries in the private_terms file.
  • Here is a sample entry:

algol
ansi
arco
arpa
arpanet
ascii

• timestamp_config
  • Default: $SPLUNK_HOME/lib/python2.4/site-packages/splunk/timestamp_config/
  • Splunk's built-in file that determines how timestamps are parsed.
• branding
  • Default: 'splunk'
  • A single-quoted string to use frequently as a replacement for anonymized words, to give the file a recognizable identity.

Output Files

Splunk's anonmyizer function will create three new files in the same directory as the source file.

• ANON-filename
  • The anonymized version of the source file.
• INFO-mapping.txt
  • This file contains a list of which terms were anonymized into which strings.
  • Here is a sample entry:

Replacement Mappings
--------------------
kb900485 --> LO200231
1718 --> 1608
transitions --> tstymnbkxno
reboot --> SPLUNK
cdrom --> pqyvi

• INFO-suggestions.txt
  • A report of terms found in the file that, based on their appearance and frequency, you may want to add to public_terms.txt or to private-terms.txt or to public-terms.txt for more accurate anonymization of your local data.
  • Here is a sample entry:

Terms to consider making private (currently not scrubbed):
['uid', 'pci', 'lpj', 'hard']
Terms to consider making public (currently scrubbed):
['jun', 'security', 'user', 'ariel', 'name', 'logon', 'for', 'process', 'domain', 'audit']

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