Is there any way to encrypt or secure log4net output?
I'm assuming you want to encrypt the log's output. In that case you will need to write your own Appender which can handle the encryption. I would suggest figuring out what output mechanism you intend to use without encryption (i.e. FileAppender, EventLogAppender, etc.), and then extend that Appender and override the functionality that actually writes out the output.
The reference documentation on the appenders can be found here.
For instance, extend the FileAppender with an EncryptedFileAppender and override/implement the members you need to in order to hook into the file writing.
Alternatively, you could extend from IAppender and create an appender completely from scratch. That would give you more control, but might require more work if all you're trying to do is encrypt your payload.
If you are attempting to prevent users from reading it over the web, you can change the filename you are writing the log records in to an extension which you do not allow to be served by your website. This way, users cannot guess at your log file and access it over the web.
If you are trying to prevent users logged on to the server itself from viewing the contents of the file, you could use permission control to lock the file down so that only users in specific administrator groups could view the contents.
Alternatively, you can log to the database so that there is no file that needs to be secured at all.
There's no out-of-the-box support for encryption. So as others have stated here, you will have to implement that yourself.
That said, I would suggest subclassing a ForwardingAppender to do the encryption. This will basically let you put your appender "in front of" whatever standard appender you would choose to do the actual writing to disk.
I realise that this answer comes a few years after the original post date, but after facing the same problem I decided to create an Open source package to do just this job: Log4Net Message Encryptor
The source code can be found on GitHub
And the package can be downloaded from NuGet
Related
I have Created a C# Desktop Windows form Application and I have created a setup for that. In the C:\Programs files app folder I have a JSON file. I need to protect it from accessing by anyone (I need to protect the data). What should I do?
You can't. If the intruder have access to the computer with the Administrator rights (or even more - a physical access to the hardware), then any protection will be useless.
You can use some kind of encryption, code obfuscation and some anti-debugging techniques to make it harder to retrieve the data, but qualified intruder with the appropriate access level will be able to access the data in the moment when you will decrypt it.
The only working way is to completely remove the secret data from the client's computer and move it to the your secure server alongside with the processing of such a data. So, client sends the inputs to your server, the server performs the processing using the secret data and sends back ready-to-use results.
First of all: it's impossible to make it un-breakable - I won't argue on this. Then you can simply encrypt it with a simple Blowfish algorithm and keep the key hardcoded.
You can use a more secure algorithm if you want so.
Easiest solution is to use a binary serialization format instead of json. This will make it much harder to understand and decode. Or just hardcode the data instead. Most people lack the knowledge to do anything meaningfull with a binary chunk of data, or an assembly for that matter.
A more complicated solution would be to sign the data, as this would allow you to only hardcode the key. A related alternative is Encryption. Encryption is sufficient but not necessary for ensuring the integrity of the data, but is not really more difficult to apply, see encrypting data.
Whatever you do you cannot really prevent a sufficiently determined and knowledgeable attacker. It is possible to decompile the program and extract or replace any secrets therein. The only truly secure way would be to prevent access to the files in the first place, by moving it to the web for example.
I had a similar requirement and decided to encrypt the data.
I used the package "AuthenticatedEncryption" (available from NuGet ) and could hard-code the key in my code.
NuGet: https://www.nuget.org/packages/AuthenticatedEncryption/
Guthub: https://github.com/trustpilot/nuget-authenticated-encryption
I can do this, as my main purpose is more to make the data unreadable to users and I don't expect it to be unbreakable.
Even so, I change the key every few releases.
For my ~70Kb JSON file I only load it once at the start of the program, so performance is not a problem. Not that I anyway notice anything!
In my application I need to read an encrypted file that is distributed with the app. I also need to connect to a download service using a password. My conundrum is where to store the passwords for these resources? In other languages, such as C++, I would just have stored them in the code. However, as there are tools that can disassemble C#, such as JetBrains DotPeek, that is not secure.
Below are the solutions I have thought of so far, but I don't think any of them are secure:
Store the passwords in the code: No good because C# can be disassembled.
Store the passwords in an encrypted external resource: No good, because then you need to store the password for that!
Ask the user for the password on first use (which they have been told by other means): No good, I think, because don't you still need to store it for subsequent use?
Store them in a C++ dll: No good, because what is to stop anyone else calling the function in that dll?
Hide and encrypt the passwords in the code: For example, don't call it password and use multiple levels of encrypting it. This would make it difficult for someone who was just text searching the code, but wouldn't stop someone prepared to debug the program to find out how the resources were accessed. No good.
Obfuscate the code base to prevent disassembly: Possibly this might work. Is it secure? Does anyone do it?
What is the normal solution to this quite typical problem?
Note: if you want the authentication to be done 100% offline, there is no truly secure way since someone that has access to the computer has access to all of it content.
First off, cpp CAN be decompiled as per this SO answer. It's just ugly as hell.
Why not just use a database which would store hashed passwords ? When the user wants to read the file or download from the service, you ask him for a password then hash it and match it with the hashed version stored in your database. The matching would of course be done over a secure protocol.
Here is a tutorial about ASP.NET auth. You may read it just to understand the way they store the password and match it.
Keep in mind that obfuscation/multiple levels of encryption won't stop someone really determined.
You haven't mentioned my answer at all in your post. Do you dislike this approach or did you not think of it ?
edit: regarding the file, since the user must not be allowed to decrypt it you could have an other "key" stored in the database. When the user authenticates with their password you retrieve the key from the database and decrypt the file. this way the user never sees the key for the file.
As per Vytautas Plečkaitis's suggesstion: you could use the has of your application as an authentication token to retrieve the password for the file from the database. The idea is good from a user-friendly point of view since it allow the user to not have to give any password but it means that the "key" to the database is the same for every instance of your application (crack it once, you cracked them all). Also, this means that to obtain the key to your application all you have to do is get the hash of your executing exe ... i'm nto a security expert (not even close to that) so i dont know how secure that is but i'm not sure that it's the best idea.
To me the password/hash/database pattern is the best, especially since it has been used over and over again for years. This is the built-in method for .NET Core authentication
Did a quick search and found this gem Encrypting app.config File which could be an option for you, just store those credentials inside the app.config. What you'd be doing here is encrypting sections of your configuration file.
You cannot encrypt the entire - it's a
configuration section group, which contains configuration sections.
The aspnet_regiis will only encrypt configuration sections - so you
need to selectively encrypt those parts you need, like this:
cd C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727
aspnet_regiis.exe -pef "system.serviceModel/bindings" .
aspnet_regiis.exe -pef "system.serviceModel/services" .
etc.
With this, you can encrypt what you need easily - what isn't too
important, can be left in clear text.
Word of warning: since it's aspnet_regiis, it expects to be dealing
with a web.config file - copy your app.config to a location and call
it web.config, encrypt your sections, and copy those encrypted
sections back into your own app.config.
Or write your own config section encrypter/decrypter - it's really
just a few lines of code! Or use mine - I wrote a small
ConfigSectionCrypt utility, come grab it off my OneDrive - with full
source (C# - .NET 3.5 - Visual Studio 2008). It allows you to encrypt
and decrypt sections from any config file - just specify the file name
on the command line.
Here is the link to the said OneDrive https://1drv.ms/u/s!AtQ29cmdYW3QgnnBpcHRRCc4_mop and it is currently active.
I'm tasked of introducing logging to a larger project. I have the following requirements:
Logging to the same file must be enabled from Visual Studio's C++ products, C# products, desktop apps, windows services, and more than one process should be able to write to a log file at once.
Format of logs is custom (semi-colon delimited fields, something like "custom_date;custom_time;the_rest;of_the_fields").
Log files have limit in size.
There's main .log file and older .bak file. .bak file is deleted when new .log file is created and current .log is renamed to .bak.
In one special case name of log files depends on time of creation. There are no multi-process writes in this case.
Now, I can roll my own implementation, but it would be really nice if there are ready made free libraries that satisfy all of the requirements. Does any one know of such libraries?
Many of your requirements (I think all but the language independence) are fulfilled by log4net
As you want to use several software components to use the logger I would suggest to write a windows service by yourself as it can be used by all types of your client software (C++, C#, ...)
Maybe you could simply write to the Event Log.
I would recommend NLog, meets most of your requirements
Use Microsoft's Enterprise Exception and Logging Application blocks. It satisfies all of your requirements. Everything is configurable using the web.config or app.config and allows the use of templates to record specific details. Also note that Microsoft has included a rolling type logger that will automatically start a new file based upon size or date/time. It's a complete package for any type of logging you want to do, MSMQ, SQL, flat file, windows event log, etc.
Log4Net can help you with your 2 and 3 point, for your 1,4 and 5 point i suggest you write a WebService that do all the work for writting in the logs, create, delete, etc.
In normal separate XML file configuration i place in my root directory my application works just fine with both appenders.
However, I have found an easy and more efficient way to configure from an external file Which allowed me the flexibility of using the same config file for different applications...
Also one more advantage is I dont need to make any modification to the global.asax and assembly.
Here is the code which i added to my web.config
<appSettings>
<add key="log4net.Config" value="C:\\log\Log4Net.config"/>
</appSettings>
This code is suppose to put the config file in my root directory. And all I needed to do was reference the log4net.dll and start logging.
Even-though my AdoNetAppender is completely working fine and i am seeing the messages instantly in my table.
But my fileAppenders arent creating any files neither logging the messages to existing files. Is this way only compatible with database or I'm missing something?
You can set the LockingModel of the RollingFileAppender to MinimalLock to force the appender to open and close the file for every logging event. Not exactly efficient, and there is still a possibility that one application will not be able to log if they try to log at the exact same time, but if your logging frequency is low enough it may be sufficient.
A better solution is to use a pattern string for the file name of the appender that includes the application name; that way, different applications can use the same config file, but will write to different log files. In most cases the "%appdomain" variable will work for that purpose (although for web or ClickOnce applications you have to get a little more creative).
It's not possible with the standard RollingFileAppender to log into one single file from multiple processes because the appender locks the file to write in it. The log4net FAQ provides a solution for this.
See log4net FAQ
Regards
By default settings are stored at: C:\Documents and Settings\\Local Settings\Application Data\<Project Name>
How can I change this path to application directory. I also don't want to have different files for different users. How make the settings global?
I tried to change the scope of the settings to "application" but then I cannot change them at runtime.
Using the default built-in behavior you can't!
Q: Why is the path so obscure? Is there any way to change/customize
it?
A: The path construction algorithm has to meet certain rigorous
requirements in terms of security,
isolation and robustness. While we
tried to make the path as easily
discoverable as possible by making use
of friendly, application supplied
strings, it is not possible to keep
the path totally simple without
running into issues like collisions
with other apps, spoofing etc.
The LocalFileSettingsProvider does not
provide a way to change the files in
which settings are stored. Note that
the provider itself doesn't determine
the config file locations in the first
place - it is the configuration
system. If you need to store the
settings in a different location for
some reason, the recommended way is to
write your own SettingsProvider. This
is fairly simple to implement and you
can find samples in the .NET 2.0 SDK
that show how to do this. Keep in mind
however that you may run into the same
isolation issues mentioned above .
I agree with Robert Harvey's answer do it yourself, or write a custom settings provider.
You can always read and write your own XML configuration files.
There are difficulties with programmatically changing settings for all users (since they come from the exe.config file, which is usually in Program Files and thus protected from write access in modern OSes). You can try making the settings application-wide but then use the ConfigurationManager to mess with the config file, similarly to the solution to this question.