VDB
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LOW

GHSA-8v8v-g73j-492j

Symfony's JsonPath Evaluates Attacker-Controlled Regular Expressions in match()/search() Without Limits — ReDoS

상세

### Description

The `JsonPath` component's `match()` and `search()` filter functions compile a caller-supplied pattern straight into `preg_match()`:

```php 'match' => @preg_match(\sprintf('/^%s$/u', $this->transformJsonPathRegex($argList[1])), $value), 'search' => @preg_match("/{$this->transformJsonPathRegex($argList[1])}/u", $value), ```

`transformJsonPathRegex()` only performs cosmetic escaping: there is no length cap, no restriction to the RFC 9485 i-regexp subset, and no bound on backtracking. An application that evaluates an attacker-influenced JSONPath expression server-side (e.g. one taken from a query parameter or API field and passed to `JsonCrawler`) can therefore be made to run a catastrophic-backtracking pattern such as `$[?search(@, "(a+)+$")]`. Evaluated against a moderately sized document, this pins a CPU core for seconds per request, so a handful of concurrent requests exhausts the worker pool: a denial of service. Because the `preg_match()` calls are prefixed with `@`, the PCRE backtrack-limit errors that would otherwise surface are suppressed, leaving no log trace.

### Conditions for exploitation

An application that evaluates an attacker-influenced JSONPath expression containing a `match()` / `search()` filter against any non-trivial JSON input.

### Resolution

`JsonCrawler` runs the `preg_match()` calls through a helper that lowers `pcre.backtrack_limit` to 10000 for the duration of the call (restoring the previous value afterwards), so a pathological pattern fails fast instead of stalling the worker.

The patch for this issue is available [here](https://github.com/symfony/symfony/commit/1ac2d47418ec23066112db1e6ca35be6fe123d14) for branch 7.4.

### Credits

Symfony would like to thank Himanshu Anand for reporting the issue and Alexandre Daubois for providing the fix.

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영향 패키지

Packagist / symfony/json-path
최초 영향 버전: 7.3.0 수정 버전: 7.4.12
수정 composer require symfony/json-path:^7.4.12
Packagist / symfony/json-path
최초 영향 버전: 8.0.0 수정 버전: 8.0.12
수정 composer require symfony/json-path:^8.0.12
Packagist / symfony/symfony
최초 영향 버전: 7.3.0 수정 버전: 7.4.12
수정 composer require symfony/symfony:^7.4.12
Packagist / symfony/symfony
최초 영향 버전: 8.0.0 수정 버전: 8.0.12
수정 composer require symfony/symfony:^8.0.12

참고