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Security audit

Vikunja Usage

Security checks for vulnerabilities and agentic risk

Overview

This Vikunja helper mostly matches its task-management purpose, but it under-discloses destructive actions and uses long-lived local tokens in a way users should review carefully.

Install only if you are comfortable giving the agent broad Vikunja account authority, including possible deletion and assignment changes. Prefer an HTTPS or otherwise trusted local endpoint, use a least-privileged token, avoid printing tokens, and require explicit confirmation before any delete operation.

A.I.G

Vulnerability Patterns
  • Insecure Skill Coding PracticesFinds exploitable flaws such as hardcoded secrets or command injection
  • Skill Instruction HijackingAlters the agent's session goals or safety constraints when the skill loads
  • Agent Memory PoisoningWrites attacker-controlled rules into memory that affect later sessions
  • Remote Payload Retrieval and ExecutionFetches external code whose behavior can change after review
  • Embedded Malicious CodeShips malicious scripts inside the skill and executes them locally
Findings (1)

T09 · Insecure Skill Coding Practices

Warning
Location
SKILL.md:19
Finding

Vikunja credentials and long-lived bearer tokens transmitted over plaintext HTTP

Content
View full analysis
Remediation
View remediation

SkillSpector

Vulnerability Patterns
  • Data ExfiltrationExternal Transmission, Env Variable Harvesting, File System Enumeration
  • Privilege EscalationExcessive Permissions, Sudo/Root Execution, Credential Access
  • MCP Tool PoisoningHidden Instructions, Unicode Deception, Parameter Description Injection
  • Prompt InjectionInstruction Override, Hidden Instructions, Exfiltration Commands
  • Supply ChainUnpinned Dependencies, External Script Fetching, Obfuscated Code
Findings (12)

External Transmission

Medium
Category
Data Exfiltration
Confidence
60% confidence
Finding

Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Content

Scanner excerpt · SKILL.md (reported line 19)May include surrounding context.

获取 Token：

bash
RESP=$(curl -s -X POST http://localhost:3456/api/v1/login \
  -H 'Content-Type: application/json' \
  -d '{"username":"your-user","password":"your-pass"}')
TOKEN=$(echo "$RESP" | grep -o '"token":"[^"]*"' | cut -d'"' -f4)

Sudo/Root Execution

Medium
Category
Privilege Escalation
Confidence
80% confidence
Finding

Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.

Content

Scanner excerpt · SKILL.md (reported line 30)May include surrounding context.

bash
mkdir -p "$AGENT_WORKSPACE/config"
echo "$TOKEN" > "$AGENT_WORKSPACE/config/.vikunja-token"
chmod 600 "$AGENT_WORKSPACE/config/.vikunja-token"

读取 Token：

External Transmission

Medium
Category
Data Exfiltration
Confidence
60% confidence
Finding

Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Content

Scanner excerpt · SKILL.md (reported line 48)May include surrounding context.

bash
# 列出项目
curl -s http://localhost:3456/api/v1/projects -H "Authorization: Bearer $TOKEN"

# 创建项目（PUT /projects）
curl -s -X PUT http://localhost:3456/api/v1/projects \

Description-Behavior Mismatch

Medium
Category
Not specified by scanner
Confidence
97% confidence
Finding

The skill documents project deletion but the manifest does not disclose destructive deletion capability. Hidden destructive actions are dangerous because users, agents, or reviewers may grant this skill broader trust than warranted, leading to unexpected permanent data loss.

Content

No source excerpt is available for this finding.

Missing User Warnings

Medium
Category
Not specified by scanner
Confidence
90% confidence
Finding

Documenting project deletion without any warning, confirmation guidance, or note about irreversibility increases the risk of accidental destructive use. In an agent context, terse examples may be copied directly into automation, causing unintended deletion of entire projects.

Content

No source excerpt is available for this finding.

Missing User Warnings

Medium
Category
Not specified by scanner
Confidence
90% confidence
Finding

The task deletion example is presented as a routine operation without a warning about irreversible removal. This is risky in an automation skill because agents may execute the example directly and remove data based on ambiguous prompts or misunderstandings.

Content

No source excerpt is available for this finding.

Description-Behavior Mismatch

Medium
Category
Not specified by scanner
Confidence
96% confidence
Finding

The manifest/description understates the skill's capabilities by omitting assignee management, while the body documents endpoints that can change task ownership. This creates a security-relevant mismatch because operators or policy systems may approve the skill for limited task management while it can also modify assignment state affecting other users' workflows.

Content

No source excerpt is available for this finding.

External Transmission

Medium
Category
Data Exfiltration
Confidence
70% confidence
Finding

Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Content

Scanner excerpt · SKILL.md (reported line 165)May include surrounding context.

md
return {"Authorization": f"Bearer {get_token()}", "Content-Type": "application/json"}

def create_task(project_id, title, **kw):
    return requests.put(f"{BASE}/projects/{project_id}/tasks",
                        json={"title": title, **kw}, headers=headers()).json()

def update_task(task_id, **kw):

External Transmission

Medium
Category
Data Exfiltration
Confidence
70% confidence
Finding

Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Content

Scanner excerpt · SKILL.md (reported line 169)May include surrounding context.

md
json={"title": title, **kw}, headers=headers()).json()

def update_task(task_id, **kw):
    return requests.post(f"{BASE}/tasks/{task_id}", json=kw, headers=headers()).json()

def search_tasks(q):
    return requests.get(f"{BASE}/tasks", params={"s": q}, headers=headers()).json()

Sudo/Root Execution

Medium
Category
Privilege Escalation
Confidence
80% confidence
Finding

Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.

Content

Scanner excerpt · _meta.json (reported line 15)May include surrounding context.

json
"persistence": null,
  "credentialSetup": {
    "type": "env_or_file",
    "description": "Login once per agent to get token. Store via $VIKUNJA_TOKEN env or write to $AGENT_WORKSPACE/config/.vikunja-token with chmod 600."
  },
  "requires": {
    "anyBinaries": ["curl"],

Natural-Language Policy Violations

Low
Category
Not specified by scanner
Confidence
80% confidence
Finding

The description forces Chinese-language instructions in a skill whose title and structure are otherwise English-facing, with no indication that the user can choose language or that the tool is intended only for a Chinese-speaking locale. This can violate language or locale policy when a specific language is imposed without opt-in.

Content

No source excerpt is available for this finding.

Description-Behavior Mismatch

Low
Category
Not specified by scanner
Confidence
80% confidence
Finding

The manifest says the skill supports completion-status toggling, which implies switching task state in either direction. The documented examples only demonstrate updating a task with done=true and do not provide any dedicated toggle behavior or example of setting done=false.

Content

No source excerpt is available for this finding.