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Security audit

Little Steve Content Inbox

Security checks for vulnerabilities and agentic risk

Overview

This skill is a local content inbox that stores and manages user-saved links, notes, and image paths in its own data files, with no evidence of hidden network access, credential use, privilege escalation, or deceptive behavior.

Before installing, understand that saved inbox content is stored locally in the skill's data files and delete commands remove records without an undo or confirmation prompt. Avoid saving secrets or highly sensitive notes unless that local storage model is acceptable.

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

Note
Location
scripts/inbox.sh:178
Finding

Predictable Temporary File Enables Symlink Overwrite and Concurrent Data Corruption

Content
View full analysis

Vulnerability Details

File Location: scripts/inbox.sh:178, scripts/inbox.sh:296, and scripts/inbox.sh:317
Vulnerability Type: Predictable temporary file, symlink following, and missing update locking
Risk Level: Low

Vulnerable Code

bash
# scripts/inbox.sh:178
' "$DB" > "$DB.tmp" && mv "$DB.tmp" "$DB"

# scripts/inbox.sh:296
' "$DB" > "$DB.tmp" && mv "$DB.tmp" "$DB"

# scripts/inbox.sh:317
jq --argjson id "$id" '.items |= map(select(.id != $id))' "$DB" > "$DB.tmp" && mv "$DB.tmp" "$DB"

The same fixed temporary path, data/items.json.tmp, is used by the add, status, and delete operations.

Technical Analysis

Shell redirection opens the predictable "$DB.tmp" path before jq runs. The script does not create the temporary file exclusively, verify that it is a regular file, reject symbolic links, or hold a lock over the read-modify-write transaction.

A local process with write access to the Skill's data directory can pre-create items.json.tmp as a symbolic link. The redirection may then follow that link and overwrite a target file writable by the account running the Skill.

Concurrent legitimate invocations also share the same temporary file and read the database independently. Their writes can interfere with one another, producing lost updates, failed moves, or corrupted archive state.

Attack Path

  1. An attacker obtains local write access to the project's data directory.
  2. The attacker creates the predictable path as a symbolic link:
    bash
    ln -s /path/to/user-writable-target data/items.json.tmp
  3. The victim invokes an operation that modifies the database:
    bash
    bash scripts/inbox.sh add --type note --title "Example" --content "Example"
  4. Shell redirection follows the symbolic link and writes generated JSON to the linked target.
  5. The subsequent mv may fail or alter database state, depending on the filesystem and path state.

Alternatively, two simultaneous add, `status ...[truncated 665 chars]

Remediation
View remediation

Remediation Suggestions

  • Create a unique temporary file in the database directory using mktemp:
    bash
    tmp_file="$(mktemp "$BASE_DIR/data/.items.json.XXXXXX")"
  • Register a cleanup trap immediately:
    bash
    trap 'rm -f -- "$tmp_file"' EXIT
  • Serialize the complete read-modify-write transaction with flock or an equivalent locking mechanism.
  • Write the transformed JSON to the unique file, verify it with jq -e, set restrictive permissions, and atomically rename it over the database:
    bash
    jq '...' "$DB" > "$tmp_file"
jq -e . "$tmp_file" >/dev/null
chmod 600 "$tmp_file"
mv -f -- "$tmp_file" "$DB"
trap - EXIT
  • Ensure the data directory is not writable by untrusted users and has restrictive ownership and permissions.
  • Apply the same safe update helper consistently to the add, status, and delete operations.

SkillSpector

Vulnerability Patterns
  • Privilege EscalationExcessive Permissions, Sudo/Root Execution, Credential Access
  • Trigger AbuseOverly Broad Trigger, Shadow Command Trigger, Keyword Baiting Trigger
  • Prompt InjectionInstruction Override, Hidden Instructions, Exfiltration Commands
  • Data ExfiltrationExternal Transmission, Env Variable Harvesting, File System Enumeration
  • Supply ChainUnpinned Dependencies, External Script Fetching, Obfuscated Code
Findings (8)

Missing User Warnings

Medium
Category
Not specified by scanner
Confidence
90% confidence
Finding

The script maps a simple natural-language command like '删除 #3' or 'delete #3' directly to an inbox deletion action with no confirmation, dry-run, or undo step visible in this file. In a chat-style interface, terse commands are easy to issue accidentally or trigger through misunderstanding, which can cause unintended data loss.

Content

No source excerpt is available for this finding.

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 · scripts/inbox.sh (reported line 18)May include surrounding context.

sh
cat > "$DB" <<JSON
{"items":[],"nextId":1}
JSON
    chmod 600 "$DB"
  fi
  if [[ ! -f "$VIEW_STATE" ]]; then
    cat > "$VIEW_STATE" <<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 · scripts/inbox.sh (reported line 24)May include surrounding context.

sh
cat > "$DB" <<JSON
{"items":[],"nextId":1}
JSON
    chmod 600 "$DB"
  fi
  if [[ ! -f "$VIEW_STATE" ]]; then
    cat > "$VIEW_STATE" <<JSON

Missing User Warnings

Medium
Category
Not specified by scanner
Confidence
94% confidence
Finding

The delete command permanently removes an item from the JSON database and only prints a message after the operation completes. There is no confirmation prompt, pre-action warning, or descriptive comment/docstring disclosing that this is an irreversible data-deletion action.

Content

No source excerpt is available for this finding.

Missing User Warnings

Low
Category
Not specified by scanner
Confidence
87% confidence
Finding

This markdown file includes a destructive operation (delete --id 1) but does not provide any caution about data removal, recoverability, or confirmation behavior. Under the markdown-specific missing-warning criterion, user-facing documentation should warn when actions may affect user data or be irreversible.

Content

No source excerpt is available for this finding.

Natural-Language Policy Violations

Low
Category
Not specified by scanner
Confidence
75% confidence
Finding

The line 输入"更多"翻页 describes pagination using a Chinese-language command, which can imply a language-specific interaction pattern. Because the policy requires avoiding forced language/locale behavior without opt-in or justification, this should be documented as language-specific or accompanied by alternatives.

Content

No source excerpt is available for this finding.

Natural-Language Policy Violations

Low
Category
Not specified by scanner
Confidence
80% confidence
Finding

This JSON file contains Chinese-language note content at L156-L157, while the rest of the dataset is primarily English-like identifiers and URLs. Under the stated policy, forcing or introducing a specific language without user choice or documented justification can be a locale-policy issue, and this file provides no such opt-in or justification.

Content

No source excerpt is available for this finding.

Natural-Language Policy Violations

Low
Category
Not specified by scanner
Confidence
76% confidence
Finding

The usage text presents a mixed but fixed set of supported commands, including Chinese-first examples such as 未读列表 and 收录, without any natural-language indication that users may choose their preferred language or locale. Under the policy, forcing a specific language or locale without explicit opt-in can be a natural-language policy concern.

Content

No source excerpt is available for this finding.