Monday, November 8, 2021

CVE-2021-41170

Description

### Impact
Versions prior 1.1.1 have allowed for passing in closures directly into the template engine. As a result values that are callable are executed by the template engine. The issue arises if a value has the same name as a method or function in scope and can therefore be executed either by mistake or maliciously. 

In theory all users of the package are affected as long as they either deal with direct user input or database values. A multi-step attack on is therefore plausible. 


### Patches
Version 1.1.1 has addressed this vulnerability. 
```php
$params = [
   'reverse' => fn($input) => strrev($input),    // <-- no longer possible with version ~1.1.1
   'value' => 'My website' 
]
TemplateFunctions::registerClosure('reverse', fn($input) => strrev($input));  // <-- still possible (and nicely isolated)
Template::embrace('

{{reverse(value)}}

', $params); ``` ### Workarounds Unfortunately only working with hardcoded values is safe in prior versions. As this likely defeats the purpose of a template engine, please upgrade. ### References As a possible exploit is relatively easy to achieve, I will not share steps to reproduce the issue for now. ### For more information If you have any questions or comments about this advisory: * Open an issue in [our repo](https://github.com/sroehrl/neoan3-template)

References to Advisories, Solutions, and Tools


References to Advisories, Solutions, and Tools

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Resourcehttps://github.com/sroehrl/neoan3-template/commit/4a2c9570f071d3c8f4ac790007599cba20e16934https://github.com/sroehrl/neoan3-template/issues/8https://github.com/sroehrl/neoan3-template/security/advisories/GHSA-3v56-q6r6-4gcw
 

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thank you Templateism for the design - You should have written the code a little more complicated - Nothing Encrypted anymore