Vulnerability Details : CVE-2023-41330
Potential exploit
knplabs/knp-snappy is a PHP library allowing thumbnail, snapshot or PDF generation from a url or a html page.
## Issue
On March 17th the vulnerability CVE-2023-28115 was disclosed, allowing an attacker to gain remote code execution through PHAR deserialization. Version 1.4.2 added a check `if (\strpos($filename, 'phar://') === 0)` in the `prepareOutput` function to resolve this CVE, however if the user is able to control the second parameter of the `generateFromHtml()` function of Snappy, it will then be passed as the `$filename` parameter in the `prepareOutput()` function. In the original vulnerability, a file name with a `phar://` wrapper could be sent to the `fileExists()` function, equivalent to the `file_exists()` PHP function. This allowed users to trigger a deserialization on arbitrary PHAR files. To fix this issue, the string is now passed to the `strpos()` function and if it starts with `phar://`, an exception is raised. However, PHP wrappers being case insensitive, this patch can be bypassed using `PHAR://` instead of `phar://`. A successful exploitation of this vulnerability allows executing arbitrary code and accessing the underlying filesystem. The attacker must be able to upload a file and the server must be running a PHP version prior to 8. This issue has been addressed in commit `d3b742d61a` which has been included in version 1.4.3. Users are advised to upgrade. Users unable to upgrade should ensure that only trusted users may submit data to the `AbstractGenerator->generate(...)` function.
Vulnerability category: Execute code
Products affected by CVE-2023-41330
- cpe:2.3:a:knplabs:snappy:*:*:*:*:*:*:*:*
Exploit prediction scoring system (EPSS) score for CVE-2023-41330
1.43%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 86 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2023-41330
Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
---|---|---|---|---|---|---|
9.8
|
CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
3.9
|
5.9
|
NIST | |
9.8
|
CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
3.9
|
5.9
|
GitHub, Inc. |
CWE ids for CVE-2023-41330
-
The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.Assigned by: security-advisories@github.com (Primary)
References for CVE-2023-41330
-
https://github.com/KnpLabs/snappy/commit/d3b742d61a68bf93866032c2c0a7f1486128b67e
Merge pull request #488 from KnpLabs/fix/security-advisory-GHSA-92rv-… · KnpLabs/snappy@d3b742d · GitHubPatch
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https://github.com/KnpLabs/snappy/security/advisories/GHSA-92rv-4j2h-8mjj
PHAR deserialization (CVE-2023-28115 patch bypass) · Advisory · KnpLabs/snappy · GitHubExploit;Mitigation;Vendor Advisory
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https://github.com/KnpLabs/snappy/security/advisories/GHSA-gq6w-q6wh-jggc
PHAR deserialization allowing remote code execution · Advisory · KnpLabs/snappy · GitHubExploit;Vendor Advisory
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