T09 · Insecure Skill Coding Practices
- Location
scripts/script.sh:5- Finding
Financial Ledger Created Without Restrictive Access Permissions
- Content
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Vulnerability Details
File Location:
scripts/script.sh, lines 5-8
Vulnerability Type: Insecure permissions on sensitive local data
Risk Level: Mediumbash DB_DIR="$HOME/.budget-tracker" DB_FILE="$DB_DIR/ledger.json" mkdir -p "$DB_DIR" [ -f "$DB_FILE" ] || echo '[]' > "$DB_FILE"Technical Analysis
The script stores personal financial records in
$HOME/.budget-tracker/ledger.json, but it does not establish a restrictive umask or explicitly assign secure permissions to the directory and file.The effective permissions therefore depend on the invoking user's environment. With a common umask of
022, the directory can be created with mode755and the ledger with mode644. If the user's home directory is traversable, other local users may consequently read transaction timestamps, amounts, categories, and notes.The initialization also does not correct unsafe permissions on an existing directory or ledger. Thus, previously created data can remain exposed even after secure creation logic is later introduced.
Attack Path
- A victim invokes the budget-tracker script, causing it to create
$HOME/.budget-trackerandledger.json. - The victim's umask permits group or world read access, such as
022, and the home directory permits traversal by another local account. - The victim records transactions containing financial amounts, categories, timestamps, and potentially sensitive notes.
- An unprivileged local attacker identifies the victim's home directory and reads
.budget-tracker/ledger.json. - The attacker extracts the victim's stored financial history without authorization.
This path requires access to another local account or process and filesystem traversal rights. It does not provide privilege escalation or remote code execution.
Impact Assessment
A successful exploit results in unauthorized disclosure of locally stored personal financial information. Exposed records can include income and expense amounts, ...[truncated 276 chars]
- A victim invokes the budget-tracker script, causing it to create
- Remediation
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Remediation Suggestions
Set restrictive permissions before creating or accessing financial data:
bash umask 077 DB_DIR="$HOME/.budget-tracker" DB_FILE="$DB_DIR/ledger.json" mkdir -p -m 700 "$DB_DIR" chmod 700 "$DB_DIR" if [ ! -f "$DB_FILE" ]; then printf '%s\n' '[]' > "$DB_FILE" fi chmod 600 "$DB_FILE"Additional hardening should include:
- Verify that
$DB_DIRis owned by the current user before using it. - Reject unexpected symbolic links for the database directory or ledger file.
- Correct permissions on existing installations, not only newly created files.
- Write ledger updates atomically through a securely created temporary file in the protected directory, then replace the original file.
- Document that the ledger contains sensitive personal information and should not be placed in a shared home directory.
- Verify that