Questions tagged [.net]
A runtime, architecture, and libraries for Microsoft Windows used for creating applications.
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Bypassing URL verification
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
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1answer
44 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
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0answers
44 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
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1answer
69 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
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1answer
115 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
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0answers
67 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
76 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
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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
75 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
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2answers
167 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
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2answers
145 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
62 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
35 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
197 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
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0answers
318 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
197 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
77 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
56 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
390 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
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1answer
85 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
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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
votes
1answer
88 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
94 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
152 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
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2answers
63 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
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2answers
237 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 ...
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0answers
23 views
Replacing single quote with double single quote (SQL Injection sanitation) [duplicate]
Let's say I want to sql inject into a site, and the textbox is for my name. My name is U'ser Smith. The code is handling the single quote by replacing any instance of ' with '' on the users input only....
2
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0answers
131 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
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0answers
109 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
896 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 ...
1
vote
1answer
737 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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0answers
157 views
Session Fixation in ASP.NET
I am testing ASP.NET application, where session id (ASP.NET_SessionId) is not renewed after login. Actually it is renewed when I use browser, on the login page server sends:
Set-Cookie: ASP....
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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
votes
1answer
78 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
194 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
435 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
157 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
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1answer
79 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
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1answer
395 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
102 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
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0answers
253 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
533 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
vote
2answers
504 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 ...
1
vote
1answer
106 views
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 it needs to call a C# process from within. In my situation, the Java app is calling this C# program https://github.com/nddipiazza/...
2
votes
2answers
118 views
How can I verify that network calls to my API come only from my C# program?
I have a desktop application build on the .Net framework.
If I obfuscate the code, even if somebody reverse-engineers the code and tries to call my API using the altered source, can I know if the API ...
1
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0answers
75 views
Example of Insecure DTD Processing in XmlSchema.Read
According to https://msdn.microsoft.com/en-us/library/mt661872.aspx and https://github.com/dotnet/roslyn-analyzers/issues/563 the code below is vulnerable to DTD expansion attack:
var src = "?...
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1answer
375 views
WPF Hide ConnectionString in MyApplication.exe.config file (or hide the whole file)
While building my Project I got a new file called MyApplication.exe.config.
This is the Content of App.config (I guess) where I also included the Connection to a DataBase in <ConnectionString>.
...
2
votes
2answers
64 views
Is it feasible to leverage DOS by triggering large numbers of application exceptions?
One key aspect of a DOS or DDOS seems to be to leverage the required computational power on the attackers side to maximize the impact on the target side. This wiki article lists many examples of such ...
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1answer
674 views
Encrypt and decrypt large files with RSA, is it possible? [closed]
Encrypt and decrypt large files with RSA, is it possible?
I need to encrypt / decrypt files and save the private key named file encoder
I've seen it's not acceptable to work on large files with RSA
Is ...
2
votes
1answer
1k views
Could Meltdown/Spectre be exploited from C#/.Net (or other managed languages or the Midori OS)?
First off yes the correct answer is patch your OS/system. That aside:
Does the memory managed features of a language like C# prevent it from being used to exploit the Meltdown security bug?
What ...
