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[CVE-2021-36748] Improper neutralization of SQL parameter in SimpleBlog module from Prestahome for PrestaShop
An SQL Injection issue in the list controller of the Prestahome Blog (aka ph_simpleblog) module before 1.7.8 for Prestashop allows a remote attacker to extract data from the database via the sb_category parameter.
Summary
- CVE ID: CVE-2021-36748
- Published at: 2021-08-20
- Advisory source: sorcery.ie
- Platform: PrestaShop
- Product: ph_simpleblog
- Impacted release: < 1.7.8
- Product author: Prestahome
- Weakness: CWE-89
- Severity: critical (9.8)
Description
This blog post details an SQLi sorcery.ie found in Blog for Prestashop (ph_simpleblog) by Prestahome.
WARNING : This exploit is actively used to deploy webskimmer to massively steal credit cards.
This exploit uses a PrestaShop front controller and most attackers can conceal the module controller’s path during the exploit so you will never know within your conventional frontend logs that it exploits this vulnerability. You will only see “POST /” inside your conventional frontend logs. Activating the AuditEngine of mod_security (or similar) is the only way to get data to confirm this exploit.
CVSS base metrics
- Attack vector: network
- Attack complexity: low
- Privilege required: none
- User interaction: none
- Scope: unchanged
- Confidentiality: high
- Integrity: high
- Availability: high
Vector string: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Possible malicious usage
- Obtain admin access
- Remove data from the associated PrestaShop
- Copy/paste data from sensitive tables to the FRONT to exposed tokens and unlock admins’ ajax scripts
- Rewrite SMTP settings to hijack emails
-
Proof of concept
https://preprod.X/module/simpleblog/list?sb_category=1%27%29%3BSELECT+0x73656c65637420736c656570283130293b+INTO+%40var_name%3Bselect+%40var_name%3Bprepare+stmt+from+%40var_name%3B+execute+stmt;--
Patch for version 1.7.7
--- a/modules/ph_simpleblog/models/SimpleBlogCategory.php
+++ b/modules/ph_simpleblog/models/SimpleBlogCategory.php
@@ -421 +421 @@ class SimpleBlogCategory extends ObjectModel
- $sql->where('l.link_rewrite = \'' . $rewrite . '\' AND l.id_lang = ' . (int) $id_lang);
+ $sql->where('l.link_rewrite = \'' . pSQL($rewrite) . '\' AND l.id_lang = ' . (int) $id_lang);
@@ -423 +423 @@ class SimpleBlogCategory extends ObjectModel
- $sql->where('l.link_rewrite = \'' . $rewrite . '\'');
+ $sql->where('l.link_rewrite = \'' . pSQL($rewrite) . '\'');
@@ -436 +436 @@ class SimpleBlogCategory extends ObjectModel
- $sql->where('l.id_simpleblog_category = ' . $id_simpleblog_category . ' AND l.id_lang = ' . (int) $id_lang);
+ $sql->where('l.id_simpleblog_category = ' . (int) $id_simpleblog_category . ' AND l.id_lang = ' . (int) $id_lang);
@@ -461 +461 @@ class SimpleBlogCategory extends ObjectModel
- $tmp_location = _PS_TMP_IMG_DIR_ . 'ph_simpleblog_cat_' . $object->id . '.' . $object->cover;
+ $tmp_location = _PS_TMP_IMG_DIR_ . 'ph_simpleblog_cat_' . (int) $object->id . '.' . $object->cover;
@@ -466 +466 @@ class SimpleBlogCategory extends ObjectModel
- $orig_location = _PS_MODULE_DIR_ . 'ph_simpleblog/covers_cat/' . $object->id . '.' . $object->cover;
+ $orig_location = _PS_MODULE_DIR_ . 'ph_simpleblog/covers_cat/' . (int) $object->id . '.' . $object->cover;
--- a/modules/ph_simpleblog/models/SimpleBlogPost.php
+++ b/modules/ph_simpleblog/models/SimpleBlogPost.php
@@ -291 +291 @@ class SimpleBlogPost extends ObjectModel
- $sql->where('sbp.id_simpleblog_post ' . $filter . ' (' . implode(',', $selected) . ')');
+ $sql->where('sbp.id_simpleblog_post ' . ($filter == 'IN' ? 'IN' : 'NOT IN') . ' (' . implode(',', array_map('intval', $selected)) . ')');
@@ -413 +413 @@ class SimpleBlogPost extends ObjectModel
- $sql->where('sbp.id_simpleblog_post ' . $filter . ' (' . implode(',', $selected) . ')');
+ $sql->where('sbp.id_simpleblog_post ' . ($filter == 'IN' ? 'IN' : 'NOT IN') . ' (' . implode(',', array_map('intval', $selected)) . ')');
@@ -504 +504 @@ class SimpleBlogPost extends ObjectModel
- $sql->where('l.link_rewrite = \'' . $rewrite . '\'');
+ $sql->where('l.link_rewrite = \'' . pSQL($rewrite) . '\'');
@@ -507 +507 @@ class SimpleBlogPost extends ObjectModel
- $sql->where('l.link_rewrite = \'' . $rewrite . '\'');
+ $sql->where('l.link_rewrite = \'' . pSQL($rewrite) . '\'');
@@ -521 +521 @@ class SimpleBlogPost extends ObjectModel
- $sql->where('l.link_rewrite = \'' . $rewrite . '\'');
+ $sql->where('l.link_rewrite = \'' . pSQL($rewrite) . '\'');
@@ -538 +538 @@ class SimpleBlogPost extends ObjectModel
- $sql->where('l.link_rewrite = \'' . $rewrite . '\' AND l.id_lang = ' . (int) $id_lang);
+ $sql->where('l.link_rewrite = \'' . pSQL($rewrite) . '\' AND l.id_lang = ' . (int) $id_lang);
@@ -540 +540 @@ class SimpleBlogPost extends ObjectModel
- $sql->where('l.link_rewrite = \'' . $rewrite . '\'');
+ $sql->where('l.link_rewrite = \'' . pSQL($rewrite) . '\'');
@@ -820 +820 @@ class SimpleBlogPost extends ObjectModel
- $sql = 'UPDATE `' . _DB_PREFIX_ . 'simpleblog_post` SET `likes` = `likes` + 1 WHERE id_simpleblog_post = ' . $id_simpleblog_post;
+ $sql = 'UPDATE `' . _DB_PREFIX_ . 'simpleblog_post` SET `likes` = `likes` + 1 WHERE id_simpleblog_post = ' . (int) $id_simpleblog_post;
@@ -822 +822 @@ class SimpleBlogPost extends ObjectModel
- $sql = 'UPDATE `' . _DB_PREFIX_ . 'simpleblog_post` SET `likes` = `likes` - 1 WHERE id_simpleblog_post = ' . $id_simpleblog_post;
+ $sql = 'UPDATE `' . _DB_PREFIX_ . 'simpleblog_post` SET `likes` = `likes` - 1 WHERE id_simpleblog_post = ' . (int) $id_simpleblog_post;
@@ -829 +829 @@ class SimpleBlogPost extends ObjectModel
- $sql = 'SELECT `likes` FROM `' . _DB_PREFIX_ . 'simpleblog_post` WHERE id_simpleblog_post = ' . $id_simpleblog_post;
+ $sql = 'SELECT `likes` FROM `' . _DB_PREFIX_ . 'simpleblog_post` WHERE id_simpleblog_post = ' . (int) $id_simpleblog_post;
@@ -838 +838 @@ class SimpleBlogPost extends ObjectModel
- $sql = 'UPDATE `' . _DB_PREFIX_ . 'simpleblog_post` SET `views` = `views` + 1 WHERE id_simpleblog_post = ' . $this->id_simpleblog_post;
+ $sql = 'UPDATE `' . _DB_PREFIX_ . 'simpleblog_post` SET `views` = `views` + 1 WHERE id_simpleblog_post = ' . (int) $this->id_simpleblog_post;
--- a/modules/ph_simpleblog/models/SimpleBlogPostType.php
+++ b/modules/ph_simpleblog/models/SimpleBlogPostType.php
@@ -68 +68 @@ class SimpleBlogPostType extends ObjectModel
- $sql->where('slug = \'' . $slug . '\'');
+ $sql->where('slug = \'' . pSQL($slug) . '\''
Other recommendations
- Upgrade the module to the most recent version
- To help improve the security of your PrestaShop installation, we recommend upgrading to the latest version. One of the benefits of upgrading is that it will disable the use of multiquery executions (separated by semicolons). However, please be aware that this will not protect your shop against SQL injection attacks that use the UNION clause to steal data. Additionally, it’s important to note that PrestaShop includes a function called pSQL, which includes a strip_tags function. This helps protect your shop against Stored XSS (also known as XSS T2) of Category 1. If a pSQL function is missing, it could potentially expose your project to critical Stored XSS vulnerabilities due to edge cases. Therefore, it’s crucial to ensure that all relevant functions are properly implemented and used consistently throughout your project.
- Change the default database prefix
ps_by a new longer arbitrary prefix. Nevertheless, be warned that this is useless against blackhats with DBA senior skills because of a design vulnerability in DBMS - Activate OWASP 942’s rules on your WAF (Web application firewall), be warned that you will probably break your backoffice and you will need to pre-configure some bypasses against these set of rules.
Timeline
| Date | Action |
|---|---|
| 18-06-2021 | Issue discovered during a pentest |
| 13-07-2021 | Reported issue to Prestahome |
| 14-07-2021 | Prestahome patched the issue in version 1.7.8 |
| 15-07-2021 | Number CVE-2021-36748 assigned |
| 18-08-2021 | Blog post released |
| 20-08-2021 | pajoda released a Nuclei template for this CVE |
Links
DISCLAIMER: The French Association Friends Of Presta (FOP) acts as an intermediary to help hosting this advisory. While we strive to ensure the information and advice provided are accurate, FOP cannot be held liable for any consequences arising from reported vulnerabilities or any subsequent actions taken.
This advisory and patch is licensed under CC BY-SA 4.0
