LoFP LoFP / legitimate users and applications may use these domains for benign purposes such as file transfers, collaborative development, or storing public content. developer tools, browser extensions, or open-source software may connect to githubusercontent.com or cdn.discordapp.com as part of normal operation. it is recommended to review the associated process (`eve_process`), user behavior, and frequency of access before classifying the activity as suspicious.

Techniques

Sample rules

Cisco Secure Firewall - Connection to File Sharing Domain

Description

The following analytic detects outbound connections to commonly abused file sharing and pastebin-style hosting domains. It leverages Cisco Secure Firewall Threat Defense logs and focuses on allowed connections (action=Allow) where the url field matches a list of known data hosting or temporary storage services. While many of these platforms serve legitimate purposes, they are frequently leveraged by adversaries for malware delivery, data exfiltration, command and control (C2) beacons, or staging of encoded payloads. This analytic is valuable for identifying potential abuse of legitimate infrastructure as part of an attacker’s kill chain. If confirmed malicious, this activity may indicate tool staging, credential dumping, or outbound data leaks over HTTP(S).

Detection logic

`cisco_secure_firewall` action=Allow EventType=ConnectionEvent url IN ("*//objects.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.com*", "*pastebin.pl*", "*pastetext.net*", "*privatlab.com*", "*privatlab.net*", "*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(src_port) as src_port
  Values(dest) as dest
  Values(dest_port) as dest_port
  Values(rule) as rule
  Values(url) as url
  Values(EVE_Process) as EVE_Process
  by src_ip, transport, action

| `security_content_ctime(firstTime)` 

| `security_content_ctime(lastTime)` 

| `cisco_secure_firewall___connection_to_file_sharing_domain_filter`