GHSA-c969-5x3p-vq3v: praisonaiagents: IMAP injection via prompt → email exfil

## 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='user@example.com" LOGOUT') ``` This produces the IMAP command: ``` SEARCH FROM "user@example.com" 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='user@example.com') ``` Produces: `FROM "user@example.com"` — 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<data> 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`.

An attacker targeting an organization running a praisonaiagents email triage agent sends a crafted inbound email with a subject containing the IMAP injection payload: `legitimate subject" FETCH 1:* (BODY[])`. When the agent autonomously processes the inbox and calls `search_emails(subject='legitimate subject" FETCH 1:* (BODY[])')`, the f-string interpolation produces the IMAP command `SUBJECT "legitimate subject" FETCH 1:* (BODY[])"`. The injected FETCH command retrieves the full body of all messages in the currently selected mailbox, exfiltrating contents including credentials, business communications, and PII. A more destructive variant appends ` UID STORE 1:* +FLAGS (\Deleted)` followed by an EXPUNGE trigger, permanently purging mailbox contents—potentially destroying audit trail evidence before an incident investigation begins.