GHSA-c969-5x3p-vq3v PraisonAI: IMAP Command Injection via Unsanitized Email Search Parameters

• PyPI praisonaiagents: < 1.6.59 → fixed in 1.6.59

Summary The email search tool in `src/praisonai-agents/praisonaiagents/tools/email_tools.py` constructs IMAP SEARCH commands by interpolating LLM-controlled parameters (from_addr, subject, query) directly into IMAP protocol strings using f-string formatting with double-quote delimiters. An attacker who can influence the arguments to the `search_emails` or `reply_email` tool (via crafted agent prompts) can inject arbitrary IMAP commands, potentially exfiltrating email data from other folders, deleting emails, or performing other unauthorized IMAP operations. Details Vulnerable code (lines 493–502): ```python criteria = [] if from_addr: criteria.append(f'FROM "{from_addr}"') if subject: criteria.append(f'SUBJECT "{subject}"') if query: criteria.append(f'TEXT "{query}"') if not criteria: criteria.append("ALL") search_str = " ".join(criteria) status, data = mail.search(None, search_str) ``` The `from_addr`, `subject`, and `query` parameters originate from LLM tool call arguments (the `search_emails` public function at line 665). These values flow through without any sanitization or escaping. The double-quote (`"`) characters in these parameters allow breaking out of the IMAP SEARCH quoted string context. Additional injection points: • Line 416: `mail.search(None, f'HEADER Message-ID "{search_id}"')` • Line 447: Same pattern in `_smtp_reply_email` • Line 542: Same pattern in `_smtp_archive_email` The `search_id` / `message_id` parameter in these functions is also LLM-controlled via the `reply_email` and `archive_email` public tool functions. Reachability: The `search_emails`, `reply_email`, and `archive_email` functions are exposed as agent tools. They are reachable when an agent is configured with email tools (EMAIL_ADDRESS + EMAIL_PASSWORD environment variables set). This is a documented deployment scenario for email-capable agents. PoC Setup: Requires an IMAP server (not run here — this is a static proof). The vulnerability is demonstrated by tracing the data flow. Positive trigger — IMAP injection via `search_emails`: An LLM agent processing a crafted prompt calls: ```python search_emails(from_addr='[email protected]" LOGOUT') ``` This produces the IMAP command: ``` SEARCH FROM "[email protected]" LOGOUT" ``` The `LOGOUT` command is injected after the prematurely closed quoted string, causing the IMAP connection to be terminated. More severe injection — exfiltrate emails from another folder: ```python search_emails(query='" SEARCH RETURN (MIN) ALL') ``` Produces: `TEXT "" SEARCH RETURN (MIN) ALL"` — injects a secondary SEARCH command. Negative control — legitimate search: ```python search_emails(from_addr='[email protected]') ``` Produces: `FROM "[email protected]"` — correct, no injection. Cleanup: No persistent changes for read-only injection. For destructive injection (DELETE, EXPUNGE), impact persists. Impact An attacker who can craft prompts that cause an LLM agent to call `search_emails` with injection payloads can: • Terminate IMAP connections (denial of service) • Inject arbitrary IMAP commands — including LIST (enumerate folders), SELECT (switch folders), FETCH (read emails from other mailboxes), STORE (modify flags), COPY/MOVE (move emails), DELETE/EXPUNGE (permanently delete emails) • Exfiltrate email contents from folders the user did not intend to expose to the agent • Permanently delete emails via injected DELETE + EXPUNGE commands The attack requires the IMAP backend to be configured (EMAIL_ADDRESS + EMAIL_PASSWORD env vars), which is a documented and common deployment for email-capable agents. Suggested remediation 1. Escape double-quote characters in IMAP parameters. Per RFC 3501, literal strings use `{n}\r\n` format or quoted strings with `\` escaping: ```python def _escape_imap_string(s: str) -> str: """Escape a string for safe use in IMAP quoted strings.""" # Use IMAP literal syntax for safety: {length}\r\n encoded = s.encode('utf-8') return f'{{{len(encoded)}}}\r\n{encoded}' ``` 2. Use IMAP literal syntax (`{n}\r\ndata`) instead of quoted strings for all user-controlled parameters. This prevents any injection regardless of content. 3. Apply the escaping to all IMAP search criteria parameters: `from_addr`, `subject`, `query`, and `search_id`/`message_id`.