Questions tagged [.net]

A runtime, architecture, and libraries for Microsoft Windows used for creating applications.

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40 views

Is there an easy way to dissect .NET Remoting traffic for reverse engineering?

I'm working on a vulnerability within an application that uses .NET Remoting. I can see from the code that there are a number of potential ways to get RCE, but due to how the application performs its ...
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2answers
72 views

Generate cryptographically safe int

How can you generate a cryptographically safe integer that falls within a range in C#? I am trying to satisfy a Veracode issue reporting CWE-331: Insufficient Entropy. Obviously the code below is not ...
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4answers
202 views

Potential Risks Using Reference Code Based Authentication For Web Based Application Form That Contains SSN

I'm currently building a web based membership application form that will require a user to enter an SSN and other identifiable information. Part of the requirements of the membership application is to ...
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1answer
41 views

How to implement Anti-CSRF method? [closed]

I have created a ASP.NET project and I want to implement Anti-CSRF method in my project. How to do that?
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26 views

How to make connection secure in ASP.NET? [duplicate]

I have created a asp.net project when I run it in browser it shows connection insecure. How to overcome this ? How to make connection secure? https://www.sendspace.com/file/x3lnd4----Image that shows ...
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57 views

What is the best way to secure web API calls from worker apps running on Windows

I have a particular problem on how to securely call web APIfrom machines that do automated data collection on documents. The computers that run code are Windows machines and the server is a Kubernetes ...
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3answers
216 views

How to delete a C# variable value permanently from memory?

I have created a variable in C#. Now I want to clear the variables value from the computer memory. Is there any way to do that? Below is my current attempt at deleting the value of recordLine, but I ...
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0answers
110 views

.NET Remoting Pentest [closed]

I am carrying out activities of Vulnerability Assessment and Penetration Test, specifically, I am testing an application written in .NET Remoting. Sniffing the communication (With Wireshark) of an ...
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1answer
71 views

Get client ip address that is not spoofed

I am using the following source code to get a client IP address, Public Shared Function GetIPAddress() As String Dim context As System.Web.HttpContext = System.Web.HttpContext.Current Dim ...
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1answer
75 views

Bypassing URL verification [closed]

I'm dealing with a URL validation function that was made by the developer (instead of using trusted methods). Here is a slightly modified version of the function: public static bool IsValidURL(...
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1answer
55 views

.Net WebClient - self signed certificate

I have two applications (.net) on two web-servers. The first application will need to do a request (via WebClient) to the second and get results. I need to ensure Encryption, data integrity, and ...
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0answers
49 views

Which attributes does DPAPI's “UseMachineProtection” use to identify a machine?

We're using DPAPIProtectedConfigurationProvider from the Windows Data Protection API to encrypt an application config file. The API offers a property called UseMachineProtection, so that the config ...
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1answer
132 views

Using different host key algorithms on sftp server and client

I need to setup a sftp client the problem i am facing is that sftp client library i am using does not support the host key algorithm supported by sftp server. Basically I am talking about the public ...
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1answer
264 views

Alternative to bcrypt in .NET Core?

I'm porting an app from Node to ASP.NET Core, and discovered that the .NET Core framework doesn't have a bcrypt implementation. There are community supported bcrypt implementations but they are very ...
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0answers
69 views

How secure is this combined sha1/md5 hash [duplicate]

Recently we outsourced some work for a website. While reviewing this code I came across the password hash function. I am in no way a security expert besides some basic knowledge (hence outsourcing ...
1
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1answer
101 views

Can I decrypt a .gpg file by using Windows CNG store/ProtectedData?

I'm creating this tool in C# that would take a .gpg file and decrypt it using Windows CNG. I get a .gpg file as my input parameter and it is encrypted with my key using WinPT. Decrypting it works with ...
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1answer
59 views

SQL injection in Windows Services?

I have many Windows services which run on the server side only. It performs few CRUD operations on a database (MySQL). There is a client application which allows a user to upload files through it to ...
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0answers
107 views

How to store SSN in asp.net web-based application on a short-term basis?

After scouring the web to find countless similar questions, I still find it important enough to ask based on my client's specific requirements. Now I know most if not all are not a lawyer, but if you'...
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2answers
197 views

BCrypt workfactor for salt?

From what I read here: How to securely hash passwords?, you're supposed to iterate the hashing. However in the implementation of BCrypt for .Net uses the workfactor (2^wf iterations) in the '...
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2answers
150 views

How to hide a process in Windows?

Is there a way to make a process hidden without using any Administrator-level priviledges? I am building an antivirus which I want to protect from malware's actions, such as ending the process, or ...
2
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0answers
64 views

Is Jil vulnerable to Friday The 13th JSON attack?

Is the .NET JSON (de-)serializer Jil vulnerable to Friday The 13th JSON attack when deserializing untrusted input? If this attack is applicable, how can it be prevented? Explanation of the attack: ...
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1answer
39 views

Revoke OAuth2 Token For Mobile App

When a user logs into my mobile app it uses OAuth to authenticate them and generates a token. The token is then checked against each subsequent request. Each user account in my application has an ...
2
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1answer
225 views

Decrypting SSL traffic using Fiddler to see requests being sent by malware written in .NET

I tried to find the GET data of some malware but it appears that this malware is encrypting traffic using SSL. When I tried to decrypt the SSL data via Fiddler, I always get nothing — only ...
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0answers
351 views

ASP.NET SOAP Service XXE

Is it possible to do any type of XXE in a service developed using default C# SOAP service framework? I ask because any type of XXE payload I try to add, even XML header, whatever I add before SOAP ...
3
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1answer
222 views

BouncyCastle and Microsoft Cng ECDH secret key mismatch

I'm trying to refactor some client-side code from BouncyCastle to Microsoft Cng. I've figured out how to convert key format(ECC key blobs) between them, but I couldn't calculate the same secret. ...
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2answers
82 views

Security risks downloading external images automatically from script

I'm a developping a program which generates images from HTML files filled with external RSS feeds data. When the RSS feed contains images, I need to check their resolution and format (for instance, if ...
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1answer
62 views

Can you fake the Host attribute of a C# URI?

I was wondering if you can fake the Uri.Host value of a string. For example, given the following code: new Uri(url.ToLower()).Host == "example.com" Is there anyway to have this boolean comparison be ...
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1answer
513 views

How to pass a localhost check for an incoming request?

I'm trying to send a request to an http server hosted on a machine. The http server is in C# and drops any packets that are not from localhost: public void Request(HttpListenerContext context) { ...
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1answer
112 views

How to prevent expired cookies from maintaining accesss?

My company has a website that was recently the target of a security audit. They found that if a hacker had obtained the browser cookies used by our .NET website for authorization, that those cookies ...
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1answer
52 views

What is a secure way to use PHP tokens in a C# application

I have a C# app that is sending post requests to and from a php script. I have token based authentication setup on the php, and I have my C# app sending the tokens, however, even with obfuscation, if ...
2
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1answer
105 views

Risks of letting the browser open local/network file system listing

Browsers do not generally allow web pages to interact with client-side file system as a security measure. I would like to know what can go wrong with the following scenario: Clicking a special ...
2
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1answer
99 views

What security precautions should we take when letting a C# application send/receive emails?

I'm writing a web application which will be able to send signed and encrypted emails to someone else outside my trust boundary. It will also retrieve S/MIME encrypted (and maybe also signed) emails ...
3
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1answer
178 views

What do you search for in Open Source code to be sure there isn't malicious code?

I realize the answers will be language specific, but I am curious what terms you would look for when checking something out on Github? I was looking for a remote administration tool that I could use ...
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2answers
73 views

Make application use encrypted credentials from a file [duplicate]

I am new to cyber security but I am working on a project where I need to use it and I don't know where to start. The application I am working on connects to Jira to retrieve data and generate ...
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2answers
252 views

How to obfuscate a assemblies binary compiled with .NET framework?

How to obfuscate a binary compile with .NET framework? Tools such as Ebowla and Pecloak.py will encrypt it but the program won't run. Even UPX can't pack it. Wondering are there any ways to obfuscate ...
2
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0answers
143 views

HTML Form to PDF vulnerabilities

I have a form where the user inputs data. On the back end, I'm taking some of that data and embedding it into a PDF using ActiveReports. I then display it back to the user and save a copy on our ...
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0answers
122 views

Veracode still reports OS command injection issue after I have applied the solution as recommendations from OWAPS and Roslyn Security Guard [closed]

Current code in my project is shown below and Veracode reports there is an OS command injection filename = Regex.Replace(filename, "[^a-zA-Z0-9_]", "_") & ".svg" ProcessStartInfo startInfo = ...
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1answer
1k views

Insecure Deserialization in C# (.NET) - How to identify and test

I have been reading up on Insecure Deserialization and how it can affect Java applications. https://owasp.org/index.php/Top_10-2017_A8-Insecure_Deserialization If the captured traffic data include ...
3
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1answer
937 views

Is .NET XmlSerializer.Deserialize(TextReader) safe?

Is the .NET method XmlSerializer.Deserialize(TextReader) safe from XML vulnerabilities (XXE, XmlBomb etc..)? Will the DTD be processed during deserialization? I can understand why XmlSerializer....
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1answer
1k views

Is CBC mode for AES still safe to use in 2018?

I'm using AES-256 CBC mode in C# to encrypt various amounts of texts. The key and IV are always generated properly randomly. However, would GCM mode provide any noticeable security gains over CBC?
2
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1answer
80 views

Will installing WinZip 22 on a server create a security vulnerability?

I've recently requested a WinZip v22 with command line installation on a Windows POC/Dev server that we're using to pilot an application that is written in .Net. In the application there is ...
3
votes
1answer
195 views

What is properly way to manage and remove symmetric key in C#

If I have a symmetric key in a byte[] array in C#, how can I erase it securely? for (int i = 0; i < array.Length; i++) { array[i] = 0; } Is this good enough?
2
votes
1answer
450 views

SSL certificate for WebAPI

We have a simple system with a REST service (WebAPI) that will be hosted on one machine (hosted on IIS on a custom port, port numer 3031) and with a website hosted on another machine that will be ...
2
votes
1answer
168 views

Automatic choice of the hash function for key derivation

This is a theoretical question: does this make sense and is secure? My goal is to strengthen the passphrase. The flow is the following: I enter a pssphrase admin1234. This passphrase is going to be ...
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1answer
82 views

Visual Studio anonymity

Recently me and me colleague was wondering about obfuscating / removing project info. If application is reverse engineered than what kind of information the engineer sees? Can he see the email of the ...
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1answer
412 views

Potentially dangerous request loads the page

I hosted an application in ASP.NET 4.0 webforms. When I am browsing hostname/DressDetail.aspx?<script>alert(313)</script>&category=1&code=76 it is showing an error message like: ...
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0answers
119 views

Best way to store AES keys (web api) while dealing with multi tenants (key per tenant)

I have some data to encrypt on my database and every tenant will have his own database so surely every tenant will have a different key. I'm searching for the best way to store the key for every ...
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0answers
279 views

ViewStateUserKey .NET CSRF protection

In a typical PHP web application you append a hidden CSRF Token in each form and this token is validated when the request is submitted in the server side. I am performing a penetration test in a .NET ...
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1answer
570 views

How to get session info out of encrypted .NET viewstate?

I am performing a penetration testing for the first time in a .NET application that instead of providing cookies for session management uses the viewstate hidden field. I am using the .NET Beautifier ...
1
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2answers
551 views

How to securely send a password from one app to another app?

See this question/answer first: When calling a process from another process, Is sending stdin password more secure than sending an ENV variable? I am a Java developer that is building an app where ...