CCE-55036-8Platform: cpe:/o:redhat:enterprise_linux:8,cpe:/o:oracle:linux:7,cpe:/o:oracle:linux:8,cpe:/o:amazon:linux:2,cpe:/o:redhat:enterprise_linux:9,cpe:/o:redhat:enterprise_linux:7,cpe:/o:centos:centos:7 | Date: (C)2024-01-08 (M)2024-04-23 |
Title:
Ensure events that modify the sudo log file are collected
Description:
Monitor the sudo log file. If the system has been properly configured to disable the use of
the su command and force all administrators to have to log in first and then use sudo to
execute privileged commands, then all administrator commands will be logged to
/var/log/sudo.log . Any time a command is executed, an audit event will be triggered as
the /var/log/sudo.log file will be opened for write and the executed administration
command will be written to the log.
Rationale:
Changes in /var/log/sudo.log indicate that an administrator has executed a command or
the log file itself has been tampered with. Administrators will want to correlate the events
written to the audit trail with the records written to /var/log/sudo.log to verify if
unauthorized commands have been executed.
Audit:
On disk configuration
Run the following command to check the on disk rules:
# SUDO_LOG_FILE_ESCAPED=$(grep -r logfile /etc/sudoers* | sed -e
's/.*logfile=//;s/,? .*//' -e 's/"//g' -e 's|/|\\/|g')
# [ -n "${SUDO_LOG_FILE_ESCAPED}" ] && awk "/^ * -w/ \
&&/"${SUDO_LOG_FILE_ESCAPED}"/ \
&&/ +-p *wa/ \
&&(/ key= *[! -~]* *$/||/ -k *[!-~]* *$/)" /etc/audit/rules.d/*.rules \
|| printf "ERROR: Variable 'SUDO_LOG_FILE_ESCAPED' is unset. \n"
Verify output of matches:
-w /var/log/sudo.log -p wa -k sudo_log_file
Running configuration
Run the following command to check loaded rules:
# SUDO_LOG_FILE_ESCAPED=$(grep -r logfile /etc/sudoers* | sed -e
's/.*logfile=//;s/,? .*//' -e 's/"//g' -e 's|/|\\/|g')
# [ -n "${SUDO_LOG_FILE_ESCAPED}" ] && auditctl -l | awk "/^ * -w/ \
&&/"${SUDO_LOG_FILE_ESCAPED}"/ \
&&/ +-p *wa/ \
&&(/ key= *[! -~]* *$/||/ -k *[!-~]* *$/)" \
|| printf "ERROR: Variable 'SUDO_LOG_FILE_ESCAPED' is unset. \n"
Verify output matches:
-w /var/log/sudo.log -p wa -k sudo_log_file
Remediation:
Edit or create a file in the /etc/audit/rules.d/ directory, ending in .rules extension, with
the relevant rules to monitor events that modify the sudo log file.
Example:
# SUDO_LOG_FILE=$(grep -r logfile /etc/sudoers* | sed -e 's/.*logfile=//;s/,?
.*//' -e 's/"//g')
# [ -n "${SUDO_LOG_FILE_ESCAPED}" ] && printf "
-w ${SUDO_LOG_FILE} -p wa -k sudo_l og_file
" >> /etc/audit/rules.d/50 -sudo.rules \
|| printf "ERROR: Variable 'SUDO_LOG_FILE_ESCAPED' is unset. \n"
Merge and load the rules into active configuration:
# augenrules --load
Check if reboot is required.
# if [[ $(auditctl -s | grep "enabled") =~ "2" ]]; then printf "Reboot
required to load rules \n"; fi
Additional Information:
Potential reboot required
If the auditing configuration is locked ( -e 2), then augenrules will not warn in any way
that rules could not be loaded into the running configuration. A system reboot will be
required to load the rules into the running configuration.
System call structure
For performance ( man 7 audit.rules ) reasons it is preferable to have all the system calls
on one line. However, your configuration may have them on one line each or some other
combination. This is important to understand for both the auditing and remediation
sections as the examples given are optimized for performance as per the man page.
Parameter:
[yes/no]
Technical Mechanism:
Remediation:
Edit or create a file in the /etc/audit/rules.d/ directory, ending in .rules extension, with
the relevant rules to monitor events that modify the sudo log file.
Example:
# SUDO_LOG_FILE=$(grep -r logfile /etc/sudoers* | sed -e s/.*logfile=//;s/,?
.*// -e s/ //g )
# [ -n ${SUDO_LOG_FILE_ESCAPED} ] && printf
-w ${SUDO_LOG_FILE} -p wa -k sudo_l og_file
>> /etc/audit/rules.d/50 -sudo.rules \\
|| printf ERROR: Variable SUDO_LOG_FILE_ESCAPED is unset. \\n
Merge and load the rules into active configuration:
# augenrules --load
Check if reboot is required.
# if [[ $(auditctl -s | grep enabled ) =~ 2 ]]; then printf Reboot
required to load rules \\n ; fi
Additional Information:
Potential reboot required
If the auditing configuration is locked ( -e 2), then augenrules will not warn in any way
that rules could not be loaded into the running configuration. A system reboot will be
required to load the rules into the running configuration.
System call structure
For performance ( man 7 audit.rules ) reasons it is preferable to have all the system calls
on one line. However, your configuration may have them on one line each or some other
combination. This is important to understand for both the auditing and remediation
sections as the examples given are optimized for performance as per the man page.
CCSS Severity: | CCSS Metrics: |
CCSS Score : 6.6 | Attack Vector: LOCAL |
Exploit Score: 1.8 | Attack Complexity: LOW |
Impact Score: 4.7 | Privileges Required: LOW |
Severity: MEDIUM | User Interaction: NONE |
Vector: AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:L | Scope: UNCHANGED |
| Confidentiality: HIGH |
| Integrity: LOW |
| Availability: LOW |
| |
References: Resource Id | Reference |
---|
SCAP Repo OVAL Definition | oval:org.secpod.oval:def:97461 |
SCAP Repo OVAL Definition | oval:org.secpod.oval:def:97429 |
SCAP Repo OVAL Definition | oval:org.secpod.oval:def:97494 |
SCAP Repo OVAL Definition | oval:org.secpod.oval:def:96236 |
SCAP Repo OVAL Definition | oval:org.secpod.oval:def:97198 |
SCAP Repo OVAL Definition | oval:org.secpod.oval:def:97166 |
SCAP Repo OVAL Definition | oval:org.secpod.oval:def:97229 |