CVE-2023-26487 (published 2023-03-04T00:15Z)

Vega is a visualization grammar, a declarative format for creating, saving, and sharing interactive visualization designs.`lassoAppend' function accepts 3 arguments and internally invokes `push` function on the 1st argument specifying array consisting of 2nd and 3rd arguments as `push` call argument. The type of the 1st argument is supposed to be an array, but it's not enforced. This makes it possible to specify any object with a `push` function as the 1st argument, `push` function can be set to any function that can be access via `event.view` (no all such functions can be exploited due to invalid context or signature, but some can, e.g. `console.log`). The issue is that`lassoAppend` doesn't enforce proper types of its arguments. This issue opens various XSS vectors, but exact impact and severity depends on the environment (e.g. Core JS `setImmediate` polyfill basically allows `eval`-like functionality). This issue was patched in 5.23.0.\n

CVSS v3 base score: 6.1, MEDIUM (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N)

Weakness information:
cwe_id: CWE-79
cwe_name: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
description: The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
extended_description: 
            Cross-site scripting (XSS) vulnerabilities occur when:
            
               Untrusted data enters a web application, typically from a web request.
               The web application dynamically generates a web page that contains this untrusted data.
               During page generation, the application does not prevent the data from containing content that is executable by a web browser, such as JavaScript, HTML tags, HTML attributes, mouse events, Flash, ActiveX, etc.
               A victim visits the generated web page through a web browser, which contains malicious script that was injected using the untrusted data.
               Since the script comes from a web page that was sent by the web server, the victim's web browser executes the malicious script in the context of the web server's domain.
               This effectively violates the intention of the web browser's same-origin policy, which states that scripts in one domain should not be able to access resources or run code in a different domain.
            
            There are three main kinds of XSS:
            
               
                  Type 1: Reflected XSS (or Non-Persistent) - 
         			The server reads data directly from the HTTP request and reflects it back in the HTTP response. Reflected XSS exploits occur when an attacker causes a victim to supply dangerous content to a vulnerable web application, which is then reflected back to the victim and executed by the web browser. The most common mechanism for delivering malicious content is to include it as a parameter in a URL that is posted publicly or e-mailed directly to the victim. URLs constructed in this manner constitute the core of many phishing schemes, whereby an attacker convinces a victim to visit a URL that refers to a vulnerable site. After the site reflects the attacker's content back to the victim, the content is executed by the victim's browser.
               
                  Type 2: Stored XSS (or Persistent) - 
               The application stores dangerous data in a database, message forum, visitor log, or other trusted data store. At a later time, the dangerous data is subsequently read back into the application and included in dynamic content. From an attacker's perspective, the optimal place to inject malicious content is in an area that is displayed to either many users or particularly interesting users. Interesting users typically have elevated privileges in the application or interact with sensitive data that is valuable to the attacker. If one of these users executes malicious content, the attacker may be able to perform privileged operations on behalf of the user or gain access to sensitive data belonging to the user. For example, the attacker might inject XSS into a log message, which might not be handled properly when an administrator views the logs.
            
               
                  Type 0: DOM-Based XSS - 
               In DOM-based XSS, the client performs the injection of XSS into the page; in the other types, the server performs the injection. DOM-based XSS generally involves server-controlled, trusted script that is sent to the client, such as Javascript that performs sanity checks on a form before the user submits it. If the server-supplied script processes user-supplied data and then injects it back into the web page (such as with dynamic HTML), then DOM-based XSS is possible.
            
            
            Once the malicious script is injected, the attacker can perform a variety of malicious activities. The attacker could transfer private information, such as cookies that may include session information, from the victim's machine to the attacker. The attacker could send malicious requests to a web site on behalf of the victim, which could be especially dangerous to the site if the victim has administrator privileges to manage that site. Phishing attacks could be used to emulate trusted web sites and trick the victim into entering a password, allowing the attacker to compromise the victim's account on that web site. Finally, the script could exploit a vulnerability in the web browser itself possibly taking over the victim's machine, sometimes referred to as "drive-by hacking."
            In many cases, the attack can be launched without the victim even being aware of it. Even with careful users, attackers frequently use a variety of methods to encode the malicious portion of the attack, such as URL encoding or Unicode, so the request looks less suspicious.
         
         

Fix information:
repo_url: https://github.com/vega/vega
commit_details: repo_url: https://github.com/vega/vega
author: Arvind Satyanarayan
author_date: 2023-01-24 16:48:08-05:00
msg: fix: lassoAppend XSS w/typecheck + array spread instead of push
repository: repo_url: https://github.com/vega/vega
repo_name: vega/vega
description: A visualization grammar.
repo_language: JavaScript
owner: vega
file_changes: filename: lasso.js
change_type: ModificationType.MODIFY
diff: @@ -1,9 +1,10 @@
 import intersect from './intersect';
-import { Bounds } from 'vega-scenegraph';
+import {Bounds} from 'vega-scenegraph';
+import {array} from 'vega-util';
 
 /**
  * Appends a new point to the lasso
- * 
+ *
  * @param {*} lasso the lasso in pixel space
  * @param {*} x the x coordinate in pixel space
  * @param {*} y the y coordinate in pixel space
@@ -11,73 +12,70 @@ import { Bounds } from 'vega-scenegraph';
  * @returns a new array containing the lasso with the new point
  */
 export function lassoAppend(lasso, x, y, minDist = 5) {
-    const last = lasso[lasso.length - 1];
+  lasso = array(lasso);
+  const last = lasso[lasso.length - 1];
 
-    // Add point to lasso if distance to last point exceed minDist or its the first point
-    if (last === undefined || Math.sqrt(((last[0] - x) ** 2) + ((last[1] - y) ** 2)) > minDist) {
-        lasso.push([x, y]);
-
-        return [...lasso];
-    }
-
-    return lasso;
+  // Add point to lasso if its the first point or distance to last point exceed minDist
+  return (last === undefined || Math.sqrt(((last[0] - x) ** 2) + ((last[1] - y) ** 2)) > minDist)
+  ? [...lasso, [x, y]]
+  : lasso;
 }
 
 
 /**
  * Generates a svg path command which draws a lasso
- * 
+ *
  * @param {*} lasso the lasso in pixel space in the form [[x,y], [x,y], ...]
  * @returns the svg path command that draws the lasso
  */
 export function lassoPath(lasso) {
-    return (lasso ?? []).reduce((svg, [x, y], i) => {
-        return svg += i == 0
-            ? `M ${x},${y} `
-            : i === lasso.length - 1
-                ? ' Z'
-                : `L ${x},${y} `;
-    }, '');
+  return array(lasso).reduce((svg, [x, y], i) => {
+  return svg += i == 0
+    ? `M ${x},${y} `
+    : i === lasso.length - 1
+    ? ' Z'
+    : `L ${x},${y} `;
+  }, '');
 }
 
 
 
 /**
  * Inverts the lasso from pixel space to an array of vega scenegraph tuples
- * 
+ *
  * @param {*} data the dataset
  * @param {*} pixelLasso the lasso in pixel space, [[x,y], [x,y], ...]
  * @param {*} unit the unit where the lasso is defined
- * 
+ *
  * @returns an array of vega scenegraph tuples
  */
 export function intersectLasso(markname, pixelLasso, unit) {
-    const { x, y, mark } = unit;
-
-    const bb = new Bounds().set(
-        Number.MAX_SAFE_INTEGER,
-        Number.MAX_SAFE_INTEGER,
-        Number.MIN_SAFE_INTEGER,
-        Number.MIN_SAFE_INTEGER
-    );
-
-    // Get bounding box around lasso
-    for (const [px, py] of pixelLasso) {
-        if (px < bb.x1) bb.x1 = px;
-        if (px > bb.x2) bb.x2 = px;
-        if (py < bb.y1) bb.y1 = py;
-        if (py > bb.y2) bb.y2 = py;
-    }
-
-    // Translate bb against unit coordinates
-    bb.translate(x, y);
-
-    const intersection = intersect([[bb.x1, bb.y1], [bb.x2, bb.y2]],
-        markname,
-        mark);
-
-    // Check every point against the lasso
-    return intersection.filter(tuple => pointInPolygon(tuple.x, tuple.y, pixelLasso));
+  const { x, y, mark } = unit;
+
+  const bb = new Bounds().set(
+    Number.MAX_SAFE_INTEGER,
+    Number.MAX_SAFE_INTEGER,
+    Number.MIN_SAFE_INTEGER,
+    Number.MIN_SAFE_INTEGER
+  );
+
+  // Get bounding box around lasso
+  for (const [px, py] of pixelLasso) {
+    if (px < bb.x1) bb.x1 = px;
+    if (px > bb.x2) bb.x2 = px;
+    if (py < bb.y1) bb.y1 = py;
+    if (py > bb.y2) bb.y2 = py;
+  }
+
+  // Translate bb against unit coordinates
+  bb.translate(x, y);
+
+  const intersection = intersect([[bb.x1, bb.y1], [bb.x2, bb.y2]],
+    markname,
+    mark);
+
+  // Check every point against the lasso
+  return intersection.filter(tuple => pointInPolygon(tuple.x, tuple.y, pixelLasso));
 }
 
 
@@ -85,26 +83,26 @@ export function intersectLasso(markname, pixelLasso, unit) {
 /**
  * Performs a test if a point is inside a polygon based on the idea from
  * https://wrf.ecse.rpi.edu/Research/Short_Notes/pnpoly.html
- * 
+ *
  * This method will not need the same start/end point since it wraps around the edges of the array
- * 
+ *
  * @param {*} test a point to test against
  * @param {*} polygon a polygon in the form [[x,y], [x,y], ...]
  * @returns true if the point lies inside the polygon, false otherwise
  */
 function pointInPolygon(testx, testy, polygon) {
-    let intersections = 0;
+  let intersections = 0;
 
-    for (let i = 0, j = polygon.length - 1; i < polygon.length; j = i++) {
-        const [prevX, prevY] = polygon[j];
-        const [x, y] = polygon[i];
+  for (let i = 0, j = polygon.length - 1; i < polygon.length; j = i++) {
+    const [prevX, prevY] = polygon[j];
+    const [x, y] = polygon[i];
 
-        // count intersections
-        if (((y > testy) != (prevY > testy)) && (testx < (prevX - x) * (testy - y) / (prevY - y) + x)) {
-            intersections++;
-        }
+    // count intersections
+    if (((y > testy) != (prevY > testy)) && (testx < (prevX - x) * (testy - y) / (prevY - y) + x)) {
+      intersections++;
     }
+  }
 
-    // point is in polygon if intersection count is odd
-    return intersections & 1;
+  // point is in polygon if intersection count is odd
+  return intersections & 1;
 }

programming_language: TypeScript