VLAN Linux Client Skill Security Report — High Risk | ClawSafe

70 /100

VLAN Linux Client Skill

Manages VLAN.CN virtual networking Linux client installation, configuration, and operations

Skill instructs users to pipe a remote script from an unverified source into bash with SSL verification disabled (-k flag), enabling trivial man-in-the-middle attack and arbitrary code execution on the target system.

Skill NameVLAN Linux Client Skill

Duration35.0s

Enginepi

⛔

Do not install this skill

Do not use this skill. The installation method (curl|sh with -k) is a textbook supply-chain attack vector. If a legitimate VLAN client is needed, install it only through official distribution channels with integrity verification (GPG signatures, checksums).

Attack Chain 4 steps

⬡

Escalation Attacker performs MITM on network path to dl.vlan.cn or compromises the domain

SKILL.md:17

⬡

Escalation Attacker serves a malicious install.sh script instead of the legitimate one

SKILL.md:17

⬡

Escalation User executes 'curl -kfsSL http://dl.vlan.cn/vlan2.0/linux/install.sh | sh' — malicious script runs as root

SKILL.md:17

◉

Impact Attacker gains full root access: backdoor installation, credential theft, persistence, lateral movement

SKILL.md:17

Findings 4 items

Severity	Finding	Location
Critical	Remote script piped to bash without integrity verification Supply Chain The skill's primary installation method is 'curl -kfsSL http://dl.vlan.cn/vlan2.0/linux/install.sh \| sh'. This fetches and executes arbitrary code from a remote HTTP(S) endpoint with no checksum, GPG signature, or content inspection. An attacker who intercepts the request (especially with -k disabling cert validation) can inject arbitrary code running as root. `curl -kfsSL http://dl.vlan.cn/vlan2.0/linux/install.sh \| sh` → Remove the curl\|sh installation method entirely. If installation guidance is needed, provide distribution-package install commands (apt, yum, dnf) or direct the user to download a binary with a published checksum and GPG signature.	`SKILL.md:17`
Critical	SSL certificate verification disabled in installation command Supply Chain The -k flag in curl disables SSL certificate verification. Combined with piping to sh, this creates a trivially exploitable MITM + RCE chain. An attacker on the network path can serve a malicious install script that compromises the system. `curl -kfsSL http://dl.vlan.cn/vlan2.0/linux/install.sh \| sh` → Remove the -k flag. Use HTTPS with proper certificate validation and add SHA256/checksum verification of the downloaded artifact before execution.	`SKILL.md:17`
High	Encourages passing passwords as plaintext command-line arguments Credential Theft The skill documents 'vlancli login <username> <password>' which exposes credentials in process arguments (visible in ps, shell history, and /proc). The 'recommended' login code method is better but the password method is still presented as a valid option. `vlancli login <用户名> <密码> [服务器地址]` → Remove the password-as-argument login example entirely. Only document interactive or environment-variable-based credential passing methods.	`SKILL.md:26`
Medium	Dangerous shell command reference in documentation body Doc Mismatch SKILL.md line 193 contains 'rm -rf /' — a destructive filesystem operation. While this is likely a documentation artifact or mistake, it is extremely dangerous if the LLM reproduces it verbatim in responses. `rm -rf /` → Remove or correct the 'rm -rf /' reference. Use specific, safe path examples (e.g., 'sudo rm -rf /usr/local/vlan') as shown elsewhere in the same document.	`SKILL.md:193`

2 Critical 5 findings

💀

Critical Dangerous Command 危险 Shell 命令

curl -kfsSL http://dl.vlan.cn/vlan2.0/linux/install.sh | sh

README.md:17

💀

Critical Dangerous Command 危险 Shell 命令

rm -rf /

SKILL.md:193

🔗

Medium External URL 外部 URL

http://dl.vlan.cn/vlan2.0/linux/install.sh

README.md:17

🔗

Medium External URL 外部 URL

https://www.vlan.cn/guide/linux-client

README.md:56

🔗

Medium External URL 外部 URL

https://www.vlan.cn

README.md:57

File Tree

2 files · 6.0 KB · 257 lines

Markdown 2f · 257L

├─ 📝 README.md Markdown 57L · 1.2 KB

└─ 📝 SKILL.md Markdown 200L · 4.8 KB

Security Positives

✓ No executable code/scripts present in the skill — pure documentation only

✓ Skill does not declare any allowed tools beyond documented CLI commands

✓ No environment variable access, no file writes, no network calls from skill code

✓ The skill correctly recommends login-code authentication over password-in-command

Scan Report

Attack Chain 4 steps

Findings 4 items

File Tree

Security Positives