In the module “Static Blocks” (posstaticblocks) from PosThemes for PrestaShop, a guest can perform SQL injection in affected versions.

Note : if ajax.php do not exists in the root module directory, you are not concerned.

Summary

  • CVE ID: CVE-2023-30189
  • Published at: 2023-04-27
  • Advisory source: Friends-Of-Presta.org
  • Platform: PrestaShop
  • Product: posstaticblocks
  • Impacted release: <= 1.0 (1.0.0 seems not concerned - no semver versionning)
  • Product author: posthemes
  • Weakness: CWE-89
  • Severity: critical (9.8)

Description

The method posstaticblocks::getPosCurrentHook() has sensitive SQL calls that can be executed with a trivial http call and exploited to forge a SQL injection.

The exploit can be used even if the module is not activated.

WARNING : This exploit is actively used to deploy webskimmer to massively steal credit cards.

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 FRONT to exposed tokens and unlock admins’ ajax scripts
  • Rewrite SMTP settings to hijack emails

Proof of concept

curl -v -X POST -d 'module_id=1%22;select(0x73656C65637420736C656570283432293B)INTO@a;prepare`b`from@a;execute`b`;--' 'https://preprod.XX/modules/posstaticblocks/ajax.php'

Patch from 1.0

--- a/posstaticblocks.php
+++ b/posstaticblocks.php
@@ -311 +311 @@ class posstaticblocks extends Module {
-            WHERE m.`id_module` = ' . $id_module);
+            WHERE m.`id_module` = ' . (int) $id_module);
@@ -316 +316 @@ class posstaticblocks extends Module {
-               $sql = 'SELECT * FROM '._DB_PREFIX_.'hook_module AS `ps` LEFT JOIN '._DB_PREFIX_.'hook AS `ph` ON `ps`.`id_hook` = `ph`.`id_hook`  WHERE `ps`.`id_module`='.$id_module.' AND `ps`.`id_shop` = '.$id_shop ;
+               $sql = 'SELECT * FROM '._DB_PREFIX_.'hook_module AS `ps` LEFT JOIN '._DB_PREFIX_.'hook AS `ph` ON `ps`.`id_hook` = `ph`.`id_hook`  WHERE `ps`.`id_module`='. (int) $id_module.' AND `ps`.`id_shop` = '. (int) $id_shop ;
@@ -333 +333 @@ class posstaticblocks extends Module {
-               $sql = 'SELECT psb.`hook_module` FROM '._DB_PREFIX_.'pos_staticblock AS psb LEFT JOIN '._DB_PREFIX_.'pos_staticblock_shop AS pss ON psb.`id_posstaticblock`= pss.`id_posstaticblock` WHERE  psb.`name_module` ="'.$name_module.'" AND pss.`id_shop` = "'.$id_shop.'"';
+               $sql = 'SELECT psb.`hook_module` FROM '._DB_PREFIX_.'pos_staticblock AS psb LEFT JOIN '._DB_PREFIX_.'pos_staticblock_shop AS pss ON psb.`id_posstaticblock`= pss.`id_posstaticblock` WHERE  psb.`name_module` ="'.pSQL($name_module).'" AND pss.`id_shop` = "'. (int) $id_shop.'"';

Be warned that there is other sensitives SQL calls inside this module accessible to administrators. Since there is thousands of injection SQL accessible to administrators on the PrestaShop’s ecosystem, these vulnerabilities are ignored to avoid mind collapse.

Other recommendations

  • It’s recommended to apply patch given or delete the module (NB : disabled it is useless)
  • 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 skill 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
2023-03-12 Issue discovered during a code review by TouchWeb
2023-03-21 Contact Author to confirm versions scope
2023-03-21 A member of Friends of Presta (FX) provide another version which need a new patch
2023-03-25 Request a CVE ID
2023-04-27 Author never answer and exploit is used to massively stole credit cards
2023-04-27 Publication of this security advisory without delay due to emergency