CVE-2019-9845: MadsKristensen.AspNetCore.Miniblog Improper Input Validation
Summary
CVE-2019-9845: MadsKristensen.AspNetCore.Miniblog subject to Improper Input Validation. Affects MadsKristensen.AspNetCore.Miniblog versions < 1.0.3. No fix is published. How to fix ↓
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Background
MadsKristensen.AspNetCore.Miniblog is a NuGet package that provides a minimalistic blogging platform for ASP.NET Core applications. It allows users to create and manage blog posts, including features like image uploads. However, versions up to 1.0.3 are vulnerable to an improper input validation issue.
Vulnerability Detail
The vulnerability in MadsKristensen.AspNetCore.Miniblog (Miniblog.Core) through 2019-01-16 allows remote attackers to execute arbitrary ASPX code. This can be achieved by exploiting an IMG element with a data: URL. The issue arises from the SaveFilesToDisk function in Controllers/BlogController.cs, which writes a decoded base64 string to a file without validating the extension. As a result, an attacker can upload a malicious ASPX file disguised as an image and execute arbitrary code on the server.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a temporary workaround, it is advised to disable file uploads in the affected version of MadsKristensen.AspNetCore.Miniblog until a patch or update is available. This can be done by modifying the application's configuration or by implementing server-side checks to reject file uploads with invalid extensions.
Conclusion
The vulnerability in MadsKristensen.AspNetCore.Miniblog (CVE-2019-9845) allows remote code execution, posing a significant risk to the security and integrity of affected systems. It is crucial to update to a non-affected version, implement proper input validation and file upload restrictions, and follow secure coding practices. For further assistance in vulnerability remediation, please contact DevNack.com.
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FAQ
This vulnerability allows remote attackers to execute arbitrary ASPX code on the server, potentially leading to unauthorized access, data breaches, or further exploitation of the affected system.
No, only versions up to and including 1.0.3 are vulnerable to this issue. It is recommended to update to a non-affected version.
While specific exploits for this vulnerability may not be publicly available, the underlying issue can be easily exploited by uploading a malicious ASPX file disguised as an image.
Yes, it is recommended to update to a version of MadsKristensen.AspNetCore.Miniblog that is not affected by this vulnerability.
There are several alternative blogging platforms available for ASP.NET Core applications that have not been reported to be vulnerable to this specific issue. It is advisable to research and choose a platform with a good security track record.
