Techniques
Sample rules
Cisco NVM - Suspicious Download From File Sharing Website
- source: splunk
- technicques:
- T1197
Description
This analytic detects suspicious downloads from common file sharing and content delivery platforms using known living-off-the-land binaries (LOLBins) such as ‘curl.exe’, ‘certutil.exe’, ‘msiexec.exe’, ‘powershell.exe’, ‘wmic.exe’, and others. It leverages Cisco Network Visibility Module logs to correlate network flow activity with process context, including command-line arguments, process path, and parent process information. These tools are often abused by adversaries and malware to retrieve payloads from public hosting platforms such as GitHub, Discord CDN, Transfer.sh, or Pastebin. This detection helps identify potential initial access, payload staging, or command and control activity using legitimate services.
Detection logic
`cisco_network_visibility_module_flowdata`
(
(process_name = "svchost.exe" process_arguments = "*-s BITS*")
OR
process_name IN (
"curl.exe", "wmic.exe", "wscript.exe", "cscript.exe", "certutil.exe",
"msiexec.exe", "hh.exe", "powershell.exe", "pwsh.exe", "powershell_ise.exe",
"installutil.exe", "certoc.exe", "bitsadmin.exe"
)
)
dest_hostname IN (
"*.githubusercontent.com*", "*anonfiles.com*", "*cdn.discordapp.com*", "*ddns.net*",
"*dl.dropboxusercontent.com*", "*ghostbin.co*", "*glitch.me*", "*gofile.io*",
"*hastebin.com*", "*mediafire.com*", "*mega.nz*", "*onrender.com*", "*pages.dev*",
"*paste.ee*", "*pastebin.*", "*pastetext.net*", "*privatlab.*",
"*send.exploit.in*", "*sendspace.com*", "*storage.googleapis.com*",
"*storjshare.io*", "*supabase.co*", "*temp.sh*", "*transfer.sh*", "*trycloudflare.com*",
"*ufile.io*", "*w3spaces.com*", "*workers.dev*"
)
| stats count min(_time) as firstTime max(_time) as lastTime
values(parent_process_arguments) as parent_process_arguments
values(process_arguments) as process_arguments
values(parent_process_hash) as parent_process_hash
values(process_hash) as process_hash
values(module_name_list) as module_name_list
values(module_hash_list) as module_hash_list
values(dest_port) as dest_port
values(aliul) as additional_logged_in_users_list
values(dest_hostname) as dest_hostname
by src dest parent_process_path parent_process_integrity_level process_path process_name process_integrity_level process_id transport
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| table
parent_process_integrity_level parent_process_path parent_process_arguments parent_process_hash
process_integrity_level process_path process_name process_arguments process_hash process_id
additional_logged_in_users_list module_name_list module_hash_list
src dest_hostname dest dest_port transport firstTime lastTime
| `cisco_nvm___suspicious_download_from_file_sharing_website_filter`