T09 · Insecure Skill Coding Practices
- Location
scripts/playlist_create.py:30- Finding
AppleScript Injection Through an Unsanitized Playlist Name
- Content
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Vulnerability Details
File Location:
scripts/playlist_create.py, lines 30-39
Vulnerability Type: AppleScript injection leading to arbitrary command execution
Risk Level: HighVulnerable Code
python def ensure_playlist(name: str): script = f''' tell application "Music" if not (exists playlist "{name}") then make new user playlist with properties {{name:"{name}"}} end if end tell ''' r = applescript(script) return r.returncode == 0, (r.stderr or r.stdout).strip()The positional
playlistcommand-line argument is passed to this function frommain()without validation:python ok, msg = ensure_playlist(args.playlist)Technical Analysis
The playlist name is inserted directly into executable AppleScript source using a Python formatted string. No escaping or parameterization is applied before the resulting script is passed to
osascript.Because the input appears inside double-quoted AppleScript string literals, a crafted playlist name can close the string and introduce additional AppleScript statements. AppleScript supports security-sensitive operations such as
do shell script, application automation, and file manipulation. Consequently, this is not limited to altering playlist behavior: successful injection can execute arbitrary shell commands in the context of the user running the skill.Escaping only quotation marks would also be insufficient as a general design. The secure approach is to keep untrusted values entirely separate from AppleScript source and pass them through
osascriptarguments.Attack Path
- An attacker causes the skill to invoke
playlist_create.pywith an attacker-controlled playlist name. argparsestores that value inargs.playlist.main()passes the value directly toensure_playlist(args.playlist).ensure_playlist()interpolates the value into two executable AppleSc ...[truncated 1225 chars]
- An attacker causes the skill to invoke
- Remediation
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Remediation Suggestions
Do not construct AppleScript by interpolating untrusted input. Pass the playlist name as an argument and retrieve it through an AppleScript
on run argvhandler. For example:python def ensure_playlist(name: str): script = ''' on run argv set playlistName to item 1 of argv tell application "Music" if not (exists playlist playlistName) then make new user playlist with properties {name:playlistName} end if end tell end run ''' r = run(["osascript", "-e", script, name]) return r.returncode == 0, (r.stderr or r.stdout).strip()Apply the same parameterization pattern to
add_track_to_playlist(), where playlist, song, and artist values are also incorporated into generated AppleScript. Additional hardening should include:- Validate playlist names for expected length and reject control characters.
- Avoid relying on manual backslash escaping as the primary defense.
- Keep all user-controlled values outside executable AppleScript source.
- Add regression tests using names containing quotation marks, backslashes, line breaks, and AppleScript-like text.
- Return a nonzero process status when a security-sensitive playlist operation fails.