প্লাগইনের নাম	Order Tip for WooCommerce
Type of Vulnerability	Parameter tampering
CVE Number	CVE-2025-6025
জরুরি অবস্থা	উচ্চ
CVE Publish Date	2025-08-14
Source URL	CVE-2025-6025

Unauthenticated Tip Manipulation in “Order Tip for WooCommerce” (<= 1.5.4) — What store owners and devs must do now

সারাংশ

On 14 August 2025 a serious vulnerability (CVE-2025-6025) affecting the WordPress plugin “Order Tip for WooCommerce” (versions <= 1.5.4) was published. The flaw allows unauthenticated attackers to manipulate tip values and set them to negative amounts, effectively creating unauthorized discounts on orders. The vendor released a fixed version (1.5.5), and this issue carries a high severity (CVSS 7.5). Below I’ll walk you through what happened, why it matters for WooCommerce stores, how attackers can abuse it, how you can detect abuse, immediate mitigations you can apply (including WAF rules), a safe developer fix, and long-term best practices for hardening checkout extensions.

This article is written from a WP-Firewall security perspective to help site owners, developers and security teams respond quickly and correctly.

---

Why this vulnerability is dangerous

• অননুমোদিত — the attacker does not need to be logged in. That drastically increases the attack surface: bots and automated scanners can probe and exploit it.
• Monetary impact — because tips are applied to order totals, a negative tip can reduce the final amount payable (or even drive totals to zero or negative), allowing attackers to obtain goods or services without paying the full price.
• Automation potential — the exploit can be scripted to target many sites quickly, enabling mass exploitation and large-scale financial abuse.
• Business effects — beyond lost revenue, exploitation can cause inventory losses, chargebacks, fraud investigations, and reputational damage.

For any WooCommerce store using “Order Tip for WooCommerce” versions <= 1.5.4, treat this as high priority.

---

What the vulnerability is (high-level technical summary)

At a high level the plugin fails to enforce server-side validation, authentication, and sanitization for the endpoint that accepts tip values. The code path:

• Accepts input (tip amount) from an HTTP request (likely via AJAX or REST) that is callable without verifying the request originates from an authenticated/authorized user.
• Fails to validate the numeric value properly (e.g., not casting to a float or checking minimum allowed values).
• Stores the supplied tip value directly into order totals (or order meta) and recalculates the total, which allows negative numeric values to act as discounts.

Because the endpoint is unauthenticated and accepts negative values, attackers can craft requests that subtract money from orders.

---

Likely attack vectors and exploitation pattern

While exact endpoint names vary by plugin, typical exploitation follows this pattern:

1. Attacker identifies a target site running the vulnerable plugin (version <= 1.5.4).
2. They send crafted HTTP requests to the plugin’s tip-update endpoint (common vectors: admin-ajax.php actions, public REST endpoints, or custom AJAX handlers).
3. The payload includes:
   • an order identifier (order_id) or order key
   • tip amount (order_tip or similar) with a negative value (e.g., -10 or -10.00)
   • possibly other parameters that the endpoint expects
4. Because the handler doesn’t verify authentication nor sanitize numeric input, the plugin stores that negative tip and recalculates the order total, reducing the amount due.
5. Attacker completes the order or triggers checkout with the reduced amount, receiving goods or services at a discount or for free.

Important note: publishing real, working exploit code can help attackers. This write-up focuses on understanding the mechanics, detection and mitigation rather than providing copyable exploit scripts.

---

Indicators of Compromise (IoCs) and detection guidance

Look for the following artifacts in logs, WooCommerce order data and site database:

• Web server / access logs:
  • POST অনুরোধ করে /wp-admin/admin-ajax.php or to plugin-specific endpoints that include query parameters or POST fields such as action=… (plugin action names), order_tip, tip, order_id, order_key and negative values (e.g., order_tip=-10).
  • Requests from unexpected user-agents or IP ranges performing many similar requests quickly.
• WooCommerce orders:
  • Orders with a tip meta key (or custom line item) having negative values.
  • Orders where the line item or fee item name contains “Tip” with a negative amount.
  • Orders with totals significantly different from cart totals (discount discrepancy).
  • Multiple small-value orders or many orders with tips exactly the same negative value across different customers or order IDs (automation sign).
• Database:
  • Search postmeta or order meta for meta_key names used by the plugin (examples: _order_tip, order_tip, custom fee keys) and values < 0.
  • Audit logs (if available) showing tip updates from unauthenticated contexts.
• Application logs:
  • Plugin-provided logs (if any) showing tip updates with no corresponding authenticated user.

Forensic steps:

• Preserve logs (web, app, database) immediately.
• Export the orders showing negative tip entries for audit.
• If you identify confirmed exploitation, pause fulfillment for the affected orders while you investigate to avoid shipping goods.

---

Immediate mitigations (when you can’t upgrade right away)

Primary recommendation: update the plugin to version 1.5.5 immediately. However, if you cannot apply the update right away (compatibility, staging verification, etc.), apply one or more of the following temporary mitigations:

1. Disable the plugin temporarily
   If tipping is not business-critical, disable the plugin until you can safely update. That removes the vulnerability immediately.
2. Turn off tip UI at checkout
   If the plugin supports toggling tip collection in admin settings, disable it until the patch is applied.
3. Restrict public AJAX/REST access via WAF or server rules
   Implement rules to block unauthenticated requests to the specific plugin endpoints. Example approaches:
   • Block requests to admin-ajax.php with suspicious actions or with negative numeric parameters.
   • Block requests that include parameters named like order_tip, tip, amount containing a leading -.
4. Add a quick application-layer validation (temporary patch)
   If you can add a small mu-plugin (must-use plugin) or site-specific code, intercept requests and enforce positive tip values before the plugin can handle them. (See example PHP code below.)
5. Rate-limit and block automation sources
   Use IP rate-limiting, bot protection and blocklists to reduce automated exploitation.
6. Monitor orders and manual review
   Add a routine to flag and manually review orders created while the site was vulnerable. Be prepared to cancel/refund suspicious orders.

---

Sample WAF signatures and firewall guidance (pseudo-rules)

Below are example rule ideas you can implement in a WAF or web application protection layer. They are intentionally generic; adapt to your platform syntax (ModSecurity, Nginx, Cloud WAF console, WP-Firewall rule UI, etc.).

Block any request to admin-ajax.php with a tip parameter that contains a negative sign:

IF request_uri CONTAINS "/wp-admin/admin-ajax.php"
  AND (ARGS:order_tip MATCHES "^\s*-\d+(\.\d+)?$"
       OR ARGS:tip MATCHES "^\s*-\d+(\.\d+)?$"
       OR ARGS:amount MATCHES "^\s*-\d+(\.\d+)?$")
THEN BLOCK

Block requests to plugin-specific endpoint paths or REST route containing negative tip values:

IF request_uri MATCHES "/wp-json/order-tip-woo/.*" 
  AND (body OR args contain "tip" WITH "-")
THEN BLOCK

Block unauthenticated AJAX actions used by the plugin (replace otw_save_tip with the actual action name if known):

IF request_uri CONTAINS "/wp-admin/admin-ajax.php" 
  AND ARGS:action == "otw_save_tip" 
  AND (NOT (cookie contains "wordpress_logged_in_"))
THEN BLOCK

Generic safety rule — deny negative numerical values in fields that normally must be non-negative:

IF any_request_arg_name IN ("tip","order_tip","amount","fee") 
  AND arg_value MATCHES "^\s*-\d+(\.\d+)?$"
THEN BLOCK or FLAG for review

Note:

• Always test WAF rules in monitoring mode before blocking to avoid false positives.
• Use logging/alerting to surface blocked attempts and refine rules rapidly.

---

Developer’s fix — how this should have been handled in plugin code

Core issues to address in code:

• Enforce authentication and capability checks for any endpoint that can modify order data. If an endpoint is meant to be public, explicitly implement server-side validation and business rules that prevent abuse.
• Always sanitize and validate numeric inputs. Cast to float and enforce min/max bounds.
• Use nonces for AJAX calls and REST permission callbacks for REST endpoints.
• Treat client-side validation as convenience only; server-side is the final gatekeeper.

Example secure handling (illustrative PHP snippet to validate a tip before applying it):

/* Example: secure tip handling for an AJAX endpoint or REST callback */
function secure_save_order_tip() {
    // Verify nonce if provided (client should send a nonce)
    if ( empty($_POST['nonce']) || ! wp_verify_nonce( sanitize_text_field($_POST['nonce']), 'save_order_tip' ) ) {
        wp_send_json_error( 'invalid_nonce', 403 );
        exit;
    }

    // Require an order ID and sanitize
    if ( empty($_POST['order_id']) ) {
        wp_send_json_error( 'missing_order_id', 400 );
    }
    $order_id = intval( $_POST['order_id'] );
    $order = wc_get_order( $order_id );
    if ( ! $order ) {
        wp_send_json_error( 'invalid_order', 400 );
    }

    // Optional: verify that the requester has permission to edit the order
    // For public endpoints this may not be possible; then enforce business constraints strictly.
    // Example: only allow order owners or admins to edit tip
    $current_user_id = get_current_user_id();
    if ( $current_user_id === 0 || (int) $order->get_user_id() !== $current_user_id ) {
        // If you must support unauthenticated tip submissions (e.g., guest tipping), ensure you still sanitize & enforce bounds
        // In most cases it's safer to require authentication for order modifications
        wp_send_json_error( 'unauthorized', 403 );
    }

    // Validate tip value
    $raw_tip = isset($_POST['order_tip']) ? $_POST['order_tip'] : '0';
    // Remove any thousands separators, currency symbols, whitespace
    $clean = preg_replace('/[^\d\.\-]/', '', $raw_tip);
    $tip = floatval( $clean );

    // Enforce non-negative tip
    if ( $tip < 0 ) {
        $tip = 0.00;
    }

    // Optional: enforce maximum tip allowed to prevent abuse
    $max_tip = 1000.00;
    if ( $tip > $max_tip ) {
        $tip = $max_tip;
    }

    // Save as order fee/line item or meta safely and recalc totals
    update_post_meta( $order_id, '_order_tip_amount', $tip );
    // Recalculate totals using WC APIs
    // ... (use WooCommerce APIs to add fee and recalc)
    wp_send_json_success( array( 'new_tip' => $tip ) );
}

মূল বিষয়গুলি:

• Never accept numeric input and directly trust it; always cast and check for allowed ranges.
• When possible, require the user to be authenticated and authorized before allowing modifications to order totals.
• Use the WooCommerce APIs to add fees and recalculate totals to avoid manual manipulation mistakes.

---

Post-exploitation recovery steps and business processes

If you confirm exploitation:

1. Preserve evidence — do not delete logs or data.
2. Identify affected orders — filter orders with negative tip values or unusual discounts.
3. Pause fulfillment — hold shipping for suspect orders until manually validated.
4. Contact payment processor — if payments were manipulated post-charge, engage your processor to understand chargeback options.
5. Notify legal/fraud teams — prepare for chargebacks and customer communications where appropriate.
6. Patch — update plugin to 1.5.5 or apply vendor-supplied patch.
7. Rotate API keys and credentials if you suspect deeper compromise.
8. Perform a full site malware scan and integrity check — while the vulnerability is not a code execution bug, attackers exploiting it may have additional motives or may have attempted other actions.
9. Review order verification process — consider two-step validation for high-value orders (manual approval, additional verification).
10. Report the incident — to your incident response team, and to your plugin vendor (if you have a private support channel).

---

How a Web Application Firewall helps (WP-Firewall perspective)

A properly configured WAF can provide immediate virtual protection while you prepare and test official patches. Key benefits:

• Block malicious patterns at the HTTP layer (e.g., negative tip values, unauthenticated actions).
• Apply virtual patches (WAF rules) instantly across many sites without touching plugin code.
• Monitor and alert on suspicious requests for rapid operational response.
• Rate-limit and fingerprint automation attempts to prevent mass exploitation.

Recommended WAF actions for this vulnerability:

• Deploy the specific signatures described earlier in “Sample WAF signatures”.
• Put those rules in “block” mode after a short monitoring period to verify no legitimate traffic is impacted.
• Add alerting to notify security and ops teams when such requests are seen.
• Optionally create a rule to enforce that AJAX endpoints modifying orders require a WordPress logged-in cookie — simple, pragmatic and effective.

WP-Firewall customers can enable virtual patching rules immediately from the management console and get continuous monitoring and reporting of blocked attempts. If you aren’t a WP-Firewall user, consider implementing equivalent rules in your hosting control panel or WAF service.

---

Longer-term defenses and hardening checklist for store owners

1. Patch management
   Maintain an update policy and test updates in staging. Prioritize critical security patches on production systems.
2. Limit the number of active checkout extensions
   Each plugin is an attack surface. Remove or replace rarely used extensions.
3. Use runtime WAF/virtual patching for rapid coverage
   A WAF provides a stop-gap when vendors are slow to release or when you cannot immediately apply patches.
4. Server and application logging
   Collect and centralize logs (web, PHP, database) and have processes to run queries/searches for suspicious activity.
5. Order review workflows
   For high-value orders, implement manual review or risk scoring.
6. Principle of least privilege
   Admin accounts should be few. Plugins should only expose public endpoints when absolutely necessary.
7. Code review and secure SDLC
   If you build or commission plugins, require security reviews and static/dynamic testing before deployment.
8. Use strong nonces & capability checks for AJAX and REST endpoints
   Nonces and REST permission callbacks are straightforward ways to limit unauthorized access.
9. Regular security audits and penetration testing
   Periodic testing often finds problems earlier than opportunistic attackers.

---

Example: quick script to find suspicious orders (admin/DB usage)

You can run a WP-CLI or direct DB query to find orders with negative tip values if the plugin stores tip in postmeta with a known meta_key (replace _order_tip_amount with the plugin’s actual meta key):

WP-CLI example:

wp db query "SELECT post_id, meta_value FROM wp_postmeta WHERE meta_key = '_order_tip_amount' AND CAST(meta_value AS SIGNED) < 0;"

SQL example:

SELECT p.ID AS order_id, p.post_date, pm.meta_value AS tip_value
FROM wp_posts p
JOIN wp_postmeta pm ON pm.post_id = p.ID
WHERE p.post_type = 'shop_order'
  AND pm.meta_key = '_order_tip_amount'
  AND CAST(pm.meta_value AS DECIMAL(10,2)) < 0;

Always backup your DB before running maintenance queries.

---

A short note for plugin developers

If you maintain checkout extensions, pay attention to:

• Permission checks even for guest workflows — if a guest workflow accepts mutable data that later affects totals, you still need strict input validation and constraints.
• Avoid relying on client-side validation or JavaScript-only checks.
• Implement a robust test suite that includes negative and boundary-value tests for numeric inputs.
• Document public endpoints explicitly and ensure they require appropriate authentication or permission checks.

---

New title and invitation: Start with essential protection free today

Protect your store with essential safeguards right away — WP-Firewall’s Basic (Free) plan includes managed firewall, unlimited bandwidth, a production-grade WAF, malware scanning, and protections against OWASP Top 10 risks. If you’re running WooCommerce and rely on third-party checkout extensions, a managed WAF can block exploitation attempts like the tip-manipulation flaw while you deploy vendor fixes.

Sign up for WP-Firewall’s free plan here

(Plans at a glance: Basic — free; Standard — $50/year adds automatic malware removal & IP list controls; Pro — $299/year adds monthly security reports, automated virtual patching, and premium managed services.)

---

Closing — overview and final recommendations

This vulnerability demonstrates a recurring lesson: any feature that touches payment or order totals must be validated and protected on the server. For store owners:

1. Patch plugin to 1.5.5 immediately (or disable the plugin until patched).
2. If you cannot patch right away, implement WAF rules blocking negative tip submissions and unauthenticated modification attempts.
3. Search your orders for signs of abuse and preserve logs if you find suspicious entries.
4. Put in place detection and alerting for similar patterns so future abuse is caught faster.

If you’d like help implementing WAF rules, performing log searches, or applying a safe virtual patch while you test updates, the WP-Firewall team can assist with step-by-step support and managed protections.

Stay safe — and treat monetary-related plugin inputs as high-risk until proven otherwise.