Security audit
Security checks for vulnerabilities and agentic risk
The skill matches its VPN setup purpose, but it uses high-privilege unverified installers, network scanning, and plaintext credential bundles in ways users should review carefully before installing.
Review this skill before use. It should only be run against a VPS you own and are authorized to configure. Prefer pinned and verified installer sources, avoid subnet scanning unless permitted by your provider, do not store the sudo or panel passwords in the generated markdown guide, and rotate credentials after setup.
SKILL.md:288Mutable 3x-ui Installer Is Downloaded and Executed with Root Privileges
references/vless-tls.md:40acme.sh Is Installed Through curl-to-Shell and Subsequently Invoked with sudo
SKILL.md:378Unverified RealiTLScanner Binary Is Executed and Used to Probe Third-Party Subnets
SKILL.md:150Unsanitized Template Values Are Interpolated into Privileged Shell Commands
SKILL.md:799Mandatory Guide Stores Administrative and VPN Credentials in Plaintext
Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
mkdir -p /home/{username}/.ssh
echo "{PUBLIC_KEY_CONTENT}" > /home/{username}/.ssh/authorized_keys
chmod 700 /home/{username}/.ssh
chmod 600 /home/{username}/.ssh/authorized_keys
chown -R {username}:{username} /home/{username}/.ssh
Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
mkdir -p /home/{username}/.ssh
echo "{PUBLIC_KEY_CONTENT}" > /home/{username}/.ssh/authorized_keys
chmod 700 /home/{username}/.ssh
chmod 600 /home/{username}/.ssh/authorized_keys
chown -R {username}:{username} /home/{username}/.ssh
Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
mkdir -p /home/{username}/.ssh
echo "{PUBLIC_KEY_CONTENT}" > /home/{username}/.ssh/authorized_keys
chmod 700 /home/{username}/.ssh
chmod 600 /home/{username}/.ssh/authorized_keys
chown -R {username}:{username} /home/{username}/.ssh
Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
mkdir -p /home/{username}/.ssh
echo "{PUBLIC_KEY_CONTENT}" > /home/{username}/.ssh/authorized_keys
chmod 700 /home/{username}/.ssh
chmod 600 /home/{username}/.ssh/authorized_keys
chown -R {username}:{username} /home/{username}/.ssh
Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.
mkdir -p /home/{username}/.ssh
echo "{PUBLIC_KEY_CONTENT}" > /home/{username}/.ssh/authorized_keys
chmod 700 /home/{username}/.ssh
chmod 600 /home/{username}/.ssh/authorized_keys
chown -R {username}:{username} /home/{username}/.ssh
YARA rule matched a known malware signature (reverse shell, backdoor, ransomware, C2 framework, or info stealer).
T_MODE=a apt upgrade -y
## Step 4: Create Non-Root User
```bash
useradd -m -s /bin/bash {username}
echo "{username}:{GENERATE_STRONG_PASSWORD}" | chpasswd
usermod -aG sudo {username}
Generate a strong random password. Tell the user to save it (needed for sudo). Then:
# Verify
groups {username}
mkdir -p /home/{username}/.ssh
echo "{PUBLIC_KEY_CONTENT}" > /home/{username}/.ssh/authorized_keys
chmod 700 /home/{username}/.ssh
chmod 600 /home/{username}/.ssh/authorized_keys
chown -R {username}:{username} /home/{username}/.ssh
DO NOT proceed without successful test!
Open a NEW connection (keep root session alive):
ssh -i ~/.ssh/{nickname}_key {username}@{SERVER_IP}
Verify sudo works:
sudo whoami
# Must output: root
If this fails -- debug permissions, do NOT disable root login:
# Check on server as root:
ls -la /home/{
The command chains a network fetch directly into privileged execution of a remote installer, minimizing opportunities for user review and integrity checks. In one step, attacker-controlled upstream content could be downloaded and run as root, leading to complete server compromise.
3x-ui install script requires root. Run with sudo:
ssh {nickname} "curl -Ls https://raw.githubusercontent.com/mhsanaei/3x-ui/master/install.sh -o /tmp/3x-ui-install.sh && echo 'n' | sudo bash /tmp/3x-ui-install.sh"
The echo 'n' answers "no" to port customization prompt -- a random port and credentials will be generated.
Tool calls are chained to bypass individual safety checks or escalate capabilities beyond what any single tool call would allow.
BBR (Bottleneck Bandwidth and RTT) dramatically improves TCP throughput, especially on lossy links -- critical for VPN performance.
ssh {nickname} 'current=$(sysctl -n net.ipv4.tcp_congestion_control); echo "Current: $current"; if [ "$current" != "bbr" ]; then echo "net.core.default_qdisc=fq" | sudo tee -a /etc/sysctl.conf && echo "net.ipv4.tcp_congestion_control=bbr" | sudo tee -a /etc/sysctl.conf && sudo sysctl -p && echo "BBR enabled"; else echo "BBR already active"; fi'
Verify:
Tool parameters are crafted to achieve unintended or unsafe behavior. Parameter abuse can bypass intended safety checks (e.g. shell=True, --force, dangerous glob patterns).
Cleanup session cookie:
ssh {nickname} "rm -f /tmp/3x-cookie"
The skill tells the agent to create a local guide file containing all passwords, access details, and instructions without a prominent warning about the sensitivity of that file. Persisting aggregated secrets in a convenient plaintext bundle materially increases blast radius if the workstation, home directory, clipboard history, sync service, or backups are compromised.
These instructions require storing all collected secrets in a local file advertised as containing all passwords and access details. Centralizing sensitive authentication data in plaintext creates an attractive single point of compromise and conflicts with the skill's own stated rule against storing passwords in files.
The fallback behavior explicitly allows revealing the full guide content in chat if SCP fails, which would place collected secrets directly into conversation history. Chat logs may be retained, exported, searched, or visible to other tools, so disclosing credentials there materially increases exposure risk.
Tool parameters are crafted to achieve unintended or unsafe behavior. Parameter abuse can bypass intended safety checks (e.g. shell=True, --force, dangerous glob patterns).
chmod 700 /home/{username}/.ssh chmod 600 /home/{username}/.ssh/authorized_keys chown -R {username}:{username} /home/{username}/.ssh rm -f /home/{username}/{nickname}_key.pub
Tell user to test from their laptop:
Tool parameters are crafted to achieve unintended or unsafe behavior. Parameter abuse can bypass intended safety checks (e.g. shell=True, --force, dangerous glob patterns).
rm -f /home/{username}/vpn-guide.md
Tell user: Методичка удалена с сервера. Убедись, что она сохранена на твоём компьютере.
The guide template embeds server login data, VPN connection artifacts, and administrative panel credentials for later retrieval. Such durable storage of live secrets increases the likelihood of compromise through local malware, accidental sharing, versioning, cloud backup, or shoulder surfing.
The template explicitly embeds the server IP, username, sudo password, panel URL, panel username, panel password, and VLESS link in markdown. This consolidates multiple live secrets and access artifacts into a single exfiltration target, making compromise of that file highly damaging.
The embedded instructions direct another model to use the saved password and install sshpass for automated password-based access to the server. That encourages propagation of credentials into additional tools and command histories, expanding the trust boundary and the opportunities for accidental leakage or misuse.
The skill explicitly states passwords must never be stored in files, yet elsewhere instructs generating a guide file containing the sudo password and panel credentials. This contradiction increases the chance that long-lived credentials will be written to disk and later exposed via local compromise, backups, sync tools, or accidental sharing.
Tool calls are chained to bypass individual safety checks or escalate capabilities beyond what any single tool call would allow.
ssh {nickname} "sudo apt update && sudo apt install -y nginx"
Tool calls are chained to bypass individual safety checks or escalate capabilities beyond what any single tool call would allow.
ssh {nickname} "sudo apt update && sudo apt install -y nginx"
Tool calls are chained to bypass individual safety checks or escalate capabilities beyond what any single tool call would allow.
ssh {nickname} "sudo apt update && sudo apt install -y nginx"
Tool calls are chained to bypass individual safety checks or escalate capabilities beyond what any single tool call would allow.
ssh {nickname} "sudo apt update && sudo apt install -y nginx"
Tool calls are chained to bypass individual safety checks or escalate capabilities beyond what any single tool call would allow.
ssh {nickname} "sudo apt update && sudo apt install -y nginx"
Tool calls are chained to bypass individual safety checks or escalate capabilities beyond what any single tool call would allow.
ssh {nickname} "sudo apt update && sudo apt install -y nginx"
Tool calls are chained to bypass individual safety checks or escalate capabilities beyond what any single tool call would allow.
ssh {nickname} "sudo apt update && sudo apt install -y nginx"
No suspicious patterns detected.