Questions tagged [.net]
A runtime, architecture, and libraries for Microsoft Windows used for creating applications.
319
questions
9
votes
2answers
440 views
How to avoid using System.String with Rfc2898DeriveBytes in C#
I am creating a .NET core webapp in C# that takes in a user password and hashes it to be stored on a server. I'm using Rfc2898DeriveBytes along with a randomly generated salt. I've read, however, that ...
3
votes
0answers
41 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 ...
2
votes
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 ...
1
vote
4answers
203 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 ...
0
votes
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?
0
votes
0answers
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 ...
0
votes
0answers
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 ...
1
vote
3answers
217 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 ...
1
vote
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 ...
0
votes
1answer
73 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 ...
0
votes
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(...
1
vote
1answer
56 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 ...
1
vote
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 ...
0
votes
1answer
133 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 ...
0
votes
1answer
269 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 ...
3
votes
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
vote
1answer
103 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 ...
0
votes
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 ...
0
votes
0answers
109 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'...
3
votes
2answers
198 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 '...
0
votes
2answers
151 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
votes
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: ...
0
votes
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
votes
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 ...
2
votes
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
votes
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.
...
0
votes
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 ...
1
vote
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 ...
1
vote
1answer
516 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) {
...
1
vote
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 ...
0
votes
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
votes
1answer
107 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
votes
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
votes
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 ...
1
vote
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 ...
1
vote
2answers
254 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
votes
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 ...
1
vote
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 = ...
1
vote
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
votes
1answer
942 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....
0
votes
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
votes
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 ...
-2
votes
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 ...
0
votes
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:
...
1
vote
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 ...
0
votes
0answers
280 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 ...
0
votes
1answer
571 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 ...
