Detection: Cisco ASA - Logging Filters Configuration Tampering

Description

This analytic detects tampering with logging filter configurations on Cisco ASA devices via CLI or ASDM. Adversaries may reduce logging levels or disable specific log categories to evade detection, hide their activities, or prevent security monitoring systems from capturing evidence of their actions. By lowering logging verbosity, attackers can operate with reduced visibility to security teams. The detection monitors for logging configuration commands (message ID 111008 or 111010) that modify logging destinations (asdm, console, history, mail, monitor, trap) without setting them to higher severity levels (5-notifications, 6-informational, 7-debugging), which may indicate an attempt to reduce logging verbosity. Investigate unauthorized logging configuration changes that reduce verbosity, especially changes performed by non-administrative accounts, during unusual hours, or without corresponding change management approval.

Search

 1`cisco_asa`
 2message_id IN (111008, 111010)
 3command = "logging *"
 4command IN (
 5  "*asdm*",
 6  "*console*",
 7  "*history*",
 8  "*mail*",
 9  "*monitor*",
10  "*trap*"
11)
12NOT command IN (
13  "*notifications*",
14  "*informational*",
15  "*debugging*",
16  "* 5*",
17  "* 6*",
18  "* 7*"
19)
20
21| fillnull
22
23| stats count
24        earliest(_time) as firstTime
25        latest(_time) as lastTime
26        values(user) as user
27        values(action) as action
28        values(message_id) as message_id
29        values(command) as command
30        values(src_ip) as src_ip
31        values(process_name) as process_name
32  by host
33
34| `security_content_ctime(firstTime)`
35
36| `security_content_ctime(lastTime)`
37
38| `cisco_asa___logging_filters_configuration_tampering_filter`

Data Source

Macros Used

Annotations

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Implementation

This search requires Cisco ASA syslog data to be ingested into Splunk via the Cisco Security Cloud TA. To ensure this detection works effectively, configure your ASA and FTD devices to generate and forward message ID 111008 and 111010. If your logging level is set to 'Notifications' or higher, these messages should already be included, else we recommend setting an event list that keeps the severity level you are using and adding the message IDs 111008 and 111010. You can find specific instructions on how to set this up here : https://www.cisco.com/c/en/us/support/docs/security/pix-500-series-security-appliances/63884-config-asa-00.html. You can also change the severity level of the above message id's to the syslog level you have currently enabled using the logging message syslog_id level severity_level command in global configuration mode. For more information, see Change the Severity Level of a Syslog Message : https://www.cisco.com/c/en/us/td/docs/security/asa/asa922/configuration/general/asa-922-general-config/monitor-syslog.html#ID-2121-000006da

Known False Positives

Admins may modify logging levels during maintenance or troubleshooting to reduce log volume. Verify against change management tickets. Filter known admin accounts during maintenance windows.

Associated Analytic Story

• Suspicious Cisco Adaptive Security Appliance Activity

Risk Based Analytics (RBA)

Risk Message:

User $user$ executed command $command$ to tamper with logging filter configuration on the Cisco ASA host $host$.

References

• https://www.cisco.com/c/en/us/td/docs/security/asa/asa-cli-reference/I-R/asa-command-ref-I-R/m_log-lz.html

Detection Testing

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

Source: GitHub | Version: 1