🛡️ Sentinel: [HIGH] Fix Terminal Injection via ANSI OSC sequences with ST terminator

.jules/sentinel.md

@@ -39,3 +39,7 @@
 **Vulnerability:** The `filterSensitiveFields` function in `src/providers/index.ts` used a manual recursive loop to drop sensitive keys, but it failed to recurse into arrays. If a configuration object contained an array with sensitive nested objects, those secrets would be leaked in debug logs.
 **Learning:** Manual object traversal for redaction is prone to edge cases (like arrays or circular references).
 **Prevention:** Use a custom replacer function with `JSON.stringify` to safely and completely redact sensitive fields across all nested structures.
+## 2026-05-11 - Terminal Injection via ANSI OSC ST sequences
+**Vulnerability:** ANSI_REGEX in `src/ansi.ts` failed to match OSC sequences terminated with the String Terminator (ST, `\u001B\\`), leaving them unstripped. `sanitizeForTerminal` then translated `\x1B` to the literal string `\x1B`, meaning the payload was bypassed entirely and printed to the terminal.
+**Learning:** Standard library `ansi-regex` packages and implementations often omit or poorly handle the String Terminator (ST) sequence, assuming OSCs only end in `\x07` (BEL).
+**Prevention:** When stripping ANSI escapes, ensure OSC (Operating System Command) regexes explicitly capture the String Terminator `(?:\u0007|\u001B\\)` to completely sanitize potentially malicious sequences like terminal hyperlinks.

src/ansi.ts

@@ -2,7 +2,7 @@
 // eslint-disable-next-line no-control-regex
 const ANSI_REGEX = new RegExp(
   [
-    "[\\u001B\\u009B][[\\]()#;?]*(?:(?:(?:(?:;[-a-zA-Z\\d\\/#&.:=?%@~_]+)*|[a-zA-Z\\d]+(?:;[-a-zA-Z\\d\\/#&.:=?%@~_]*)*)?\\u0007)",
+    "[\\u001B\\u009B][[\\]()#;?]*(?:(?:(?:(?:;[-a-zA-Z\\d\\/#&.:=?%@~_]+)*|[a-zA-Z\\d]+(?:;[-a-zA-Z\\d\\/#&.:=?%@~_]*)*)?(?:\\u0007|\\u001B\\\\))",
     "(?:(?:\\d{1,4}(?:;\\d{0,4})*)?[\\dA-PR-TZcf-nq-uy=><~]))",
   ].join("|"),
   "g",

tests/ansi_security.test.ts

@@ -113,6 +113,12 @@ describe("sanitizeForClipboard", () => {
     expect(sanitizeForClipboard(input)).toBe("Red Text");
   });
 
+  test("strips ANSI OSC sequences with String Terminator (ST)", () => {
+    const input =
+      "\u001b]8;;http://malicious.com\u001b\\Malicious Link\u001b]8;;\u001b\\";
+    expect(sanitizeForClipboard(input)).toBe("Malicious Link");
+  });
+
   test("preserves tab and newline; normalises CRLF to LF", () => {
     expect(sanitizeForClipboard("Line 1\n\tIndented\r\nLine 2")).toBe(
       "Line 1\n\tIndented\nLine 2",