Found a guide for NetScaler (Citrix ADC) CVE-2023-3519 that explains how to validate and check for (currently) known Indicators of Compromise (IoCs) on a local CITRIX device.
The full guide including the commands, can be found here: [Checklist for Citrix ADC CVE-2023-3519](https://www.deyda.net/index.php/en/2023/07/19/checklist-for-citrix-adc-cve-2023-3519/)
Please bear in mind that this is a guide "found on the internet". Although it appears to be reliable and it was mentioned by SANS stormcast, these devices are not my specific area of expertise. Use your brain and use at your own risk...
Here are some key points from the article:
1. **Log in with nsroot or another administrative account.**
2. **Find out the time of the last update.** - This command lists the details of the files in the /var/nsinstall directory, which can help determine when the last update occurred.
```
shell ls -ll /var/nsinstall
```
3. **Check whether certain files have been adjusted since the last update.** - These commands find and list files in specified directories that have been modified since the last update.
```
shell
find /netscaler/ns_gui/ -type f -name *.php -newermt {Timestamp of Installer Files +1} -exec ls -l {} \;
find /var/vpn/ -type f -newermt {Timestamp of Installer Files +1} -exec ls -l {} \;
find /var/netscaler/logon/ -type f -newermt {Timestamp of Installer Files +1} -exec ls -l {} \;
find /var/python/ -type f -newermt {Timestamp of Installer Files +1} -exec ls -l {} \;
```
4. **Check for HTTP error log files.** - These commands search for .sh and .php entries in the HTTP error log files.
```
zgrep '\.sh' /var/log/httperror.log*
zgrep '\.php' /var/log/httperror.log*
```
5. **Check for Shell log files.** - This command searches for entries related to '/flash/nsconfig/keys' in the shell log files.
```
grep '/flash/nsconfig/keys' /var/log/sh.log*
```
6. **Check log files for known IOCs.** - This command finds and lists files with root permissions that have been modified since the last update.
```
find /var -perm -4000 -user root -not -path "/var/nslog/*" -newermt {Timestamp of Installer Files +1} -exec ls -l {} \;
```
7. **Check for Nobody processes.** - This command lists processes running under the 'nobody' user that are not associated with '/bin/httpd'.
```
shell ps aux | grep nobody | grep -v '/bin/httpd'
```
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