as the title states I don't understand the relation between permission to access a db and the permission to write/read files on the underlying OS.
In one of my latest CTF's I had to obtain access to a database and then read files of the server containing the flag. I know this is only possible if the compromised user has the file privilege, but my question remains the same.
Sqlmap states in its features it can accomplish this:
Support to download and upload any file from the database server underlying file system when the database software is MySQL, PostgreSQL or Microsoft SQL Server.
Now my specific questions:
What is the core feature/problem that allows this OS access?
Why are the permission connected?
Are other DBMS also vulnerable to this and is it a general problem (meaning sqlmap just doesn't provide the exploit for other dbms yet)?
In my eyes the permissions should be treated differently and the db user should not have permissions on the OS, except the files with relation to the DBMS.
Thanks in advance, I know the question is not limited to one aspect and contains various fundamental topics. I'm also willing to do more research, but maybe there is an answer that facilitates my learning process.
I am not sure about the others, but the below is true of MySQL and MariaDB.
You would need an additional exploit for local privilege escalation to gain access to any files the database user has no access to. The file path available for access is in the system variable secure_file_priv. Dumping/loading data from any other location will not be possible.
Additionally, executing commands is not possible without a UDF plugin that would allow you to execute arbitrary commands. Such things exist, but are not part of MySQL / MariaDB - it is something the sysadmin/DBA on the DB server would have to install themselves. Without this, you wouldn't be able to get the list of files.
Then there are the OS level protections:
1) POSIX level privileges
This is regular user/group file systems permissions.
2) Secondary hardening, e.g. SELinux or AppArmor
This will prevent the running process from accessing paths, ports and other resources that don't match the context or path defined in the security policy.
In short, you cannot access/retrieve arbitrary files through the database layer unless the server is deliberately (mis)configured in a way that would allow you to do so, and it would take active effort to configure a MySQL or MariaDB server in a way that would leave it open to this.
Related
I have a situation where I would like a desktop application to be useable whether an internet connection is present or not.
I have a choice of MySQL on a web server and I could work with a local MySQL database or maybe MS Access database on the local drive and then just update data when connection is restored. My issues are as follows.
Sync local changes to remote server. Multi site / multi user scenario so how to keep db in sync when connection restored without loosing changes from other users in server data.
Sync remote changes to local. Multi site / multi user scenario so how to keep db in sync when connection restored without loosing changes made locally while updating with server data.
Currently I am using XML files and LingtoXML querying but it is unsatisfactory to continue with these files so a better solution is required.
Any help would be appreciated to identify what technology would work best and how to keep them in sync.
Thanks in Advance.
"Jet Replication Objects (JRO)", the replication features of the Access Database Engine, have been deprecated (ref: here). I believe that the related management features have also been completely removed from Access 2013. Therefore, native Access replication should no longer be considered a viable option.
Microsoft's recommendation would be to use SQL Server and its replication features. However, SQL Server Express has limitations on how much it can do (e.g., it can be a "Subscriber" but not a "Publisher" or "Distributor", ref: here) so presumably there would have to be a non-free copy of SQL Server involved somehow.
I haven't yet had the occasion to use MySQL replication myself, but it is probably worth considering. Chances are good that you could still use Access as a front-end (via ODBC linked tables).
I own a machine running third party software. I input data into this software and it stores that data into its own mysql database. I'd like query the mysql database directly, but I don't know the credentials that the application is using.
I have read and write access for all files in the machine, including the files in the mysql data directory. Theoretically, I should be able to read the data directly from these files (.ibd and .frm files). But practically, I don't know where to start. I'm thinking that these data files are somewhat readable since encrypting them would destroy their index-ability.
Is this feasible? Or would I have to reverse engineer the data file format in order to read it?
Or even better - is there some config file that I can change which would implicitly trust all local connections similar to postgres?
You could read the mysql files directly, but even if they're now encrypted, the columns names might be weird and you could have to spend some time reading them.
Another point could be looking for config files from that software, that could have the login/password (very very low probability, but who knows?)
And the best would be:
make a backup of the mysql files
in another mysql instalation / computer (to not break your software), follow the reset mysql password guide
Try accessing it via the command line on the local machine:
shell> mysql db_name
(from MySQL documentation)
From here, you can create yourself an account if you need to connect from other client software.
Or have you already tried that?
If you have root access to the machine that MySQL is running on, then you can reset the MySQL root password by following the procedure at: http://www.cyberciti.biz/tips/recover-mysql-root-password.html. Once you've reset the root password, you can then login to MySQL as the root MySQL user, and access any of the databases, and query them. The only caveat to keep in mind is that changing the MySQL root password could potentially prevent your application from accessing the MySQL database, but that would be surprising as the application should be designed to connect to the database using a MySQL user account (with limited privileges) other than the root MySQL user.
At first I searched in Stack Overflow about the difference between MySQL and SQLite. So there is some answers but still I want to know something. When accessing MySQL I need to give host, username, password and database parameters. But when accessing SQLite I just give database name. Can anyone explain me this why, and for security reasons also, should not be there password for SQLite database, can not be it just downloaded for example from server, so I am totally stuck. So need your help.
The difference is that MySQL is a database server, while SQLite is a database engine that works against single database files.
You are correct that the SQLite database file could just be downloaded if it's placed right in the web application where anyone can reach it.
Most server providers offer a folder where you can place files like this, so that the web application itself can reach it, but it's not directly downloadable.
You can also optionally add protection to the SQLite database file. See this question:
Password Protect a SQLite DB. Is it possible?
SQLite is mainly used for mobile and tablet apps.So they are just used for a single system.
But in MySql its a complete database and can be used from multiple system. So for increasing security ,we have to give all these. So that no one can misuse the data...
SQLite is just a file. If you have read access to the file that is the implicit security model (as well as the possibility to use database encryption).
MySQL is a network service. It can listen on an internet facing socket, meaning anyone in the world can access it if they have the right authentication credentials.
SQLite is file based, MySQL is a service which runs on the server. With SQLite you don't need to enter the database name, but actually the database file.
If you put the database file at an inaccessible location, you should be totally fine and the user will not be able to download the file.
I am trying to configure the Apache FtpServer for windows, and i've got most of it running already, however I am having difficulty understanding the database user manager...
I am more or less a complete newbie to this and SQL, however I already have an FTP server up and running in Linux using VSFTPD. the company wants to migrate from linux to windows, and I have to create accounts for close to 5,000 users (which is why I want to use the database manager).
Here are my questions:
I can see that the xml configuration controls the connection to the database, but how does it control authentication? can someone explain which section handles user authentication from the database? EDIT: by user authentication, I do not mean the database connection itself, but rather how FTPServer authenticates a connection THROUGH the database.
How can I prevent / detect brute-force attempts against my server? our current linux ftp server uses DenyHosts for port 22 (ssh) and is hit by attacks at LEAST 20+ times a week, is there any kind of built-in authentication protection, and if not, can anyone suggest a way to create one? I know that the xml config has themax-login-failuressetting, which closes the connection after a certain number of attempts, but I need it to completely deny any further access from that IP, and not just close the connection.
Example:
Any attempt to log in with the following usernames results in immediate IP-BAN:
Root
Admin
Administrator
System
etc
Other settings
Attempts for non-existing users results in IP-BAN after # attempts for IP (including different users)
Attempts for existing users results in 60-second time out after # attempts (including different users)
Any and all help would be greatly appreciated. If you have any questions or require clarification on anything, please post a comment and I will make any necessary changes / replies.
Thanks.
See the example under Data source configuration here
Apache Ftpserver does not provide this functionallity out of the box. You either have to extend it and program this yourself, or use some external system that parses its log files and dynamically add/remove firewall rules (something like what fail2ban does on linux)
Tackling a strange scenario here.
We use a proprietary workstation management application which uses mySQL to store its data. Within the application they provide number of reports, such as which user logged into which machine at what time, all the software products installed on the monitored machines, so on and so forth. We are looking to do a different set of reports, however, they do not support custom reports.
Since their data is being stored in mySQL, I gather I can do the reporting manually. I don't have valid credentials to connect to the mySQL server though. Is there anyway for me to create a user account in the mySQL server? I do not want to reset the root password or anything account that might be in there, as it might break the application.
I have full access to the Windows 2003 server. I can stop and restart services, including the mySQL server. To the actual mySQL server, I only have basic access through the GUI provided by the software. I can't connect to it directly through CLI or through another tool (due to the lack of credentials).
I apologize if it came off as if I'm trying to get unauthorized access to the mySQL server. I have contacted the software company, and as of today it's been two weeks without a response from them. I need to get to the data. I have full access to the physical box, I have admin privileges on it.
You'll want to use the MySQL password recovery process. Follow these instructions, except replace the password reset query with a query to add a new user. The new user query would be something like:
GRANT ALL ON *.* TO 'myuser'#'localhost' IDENTIFIED BY 'mypassword' WITH GRANT OPTION;
That will create a new user "myuser" with the password "mypassword", who may log in to MySQL through the local system's CLI. You can then use the MySQL Administrator GUI (download here) and update user permissions so you can log in from other systems on the network. Or use the GRANT statement from the CLI, if that's more your style.
Do you have access to the MySQL server in question?
As in, what access do you have beyond what a regular user would? You should try to go through those routes before you "hack" your way in there, since that may or may not be feasible with that software.
odds are there are triggers on the database side keeping a log so when you hack yourself into the database they will know when and how you did it. Not a good idea.
I assume I really should not answer this one, but it's just too much fun.
Look at This page about SQL injections. That should cover your needs.
This page shows how to add user accounts to mySQL
I would try entering the following in random user input fields:
p'; INSERT INTO user VALUES
('localhost','myNewAdmin',PASSWORD('some_pass'),
'Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y');
and then
p'; FLUSH PRIVILEGES;
p'; is intended to close the regular question. e.g -
Normal question is:
"Select Adress from cusomers where custName = ' + $INPUT + ';
becomes
Select Adress from cusomers where custName = 'p'; INSERT INTO user
VALUES('localhost','myNewAdmin',PASSWORD('some_pass'),
'Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y');
One thing that comes in mind is sniffing the database communication and hope it's not encrypted. If it is encrypted try changing the configuration not to use SSL and restart mysql. A good sniffer that I use is Wireshark
From mysql 5.0 documentation:
MySQL supports secure (encrypted)
connections between MySQL clients and
the server using the Secure Sockets
Layer (SSL) protocol. This section
discusses how to use SSL connections.
It also describes a way to set up SSH
on Windows. For information on how to
require users to use SSL connections,
see the discussion of the REQUIRE
clause of the GRANT statement in
Section 12.5.1.3, “GRANT Syntax”.
The standard configuration of MySQL is
intended to be as fast as possible, so
encrypted connections are not used by
default. Doing so would make the
client/server protocol much slower.
Encrypting data is a CPU-intensive
operation that requires the computer
to do additional work and can delay
other MySQL tasks. For applications
that require the security provided by
encrypted connections, the extra
computation is warranted.
MySQL allows encryption to be enabled
on a per-connection basis. You can
choose a normal unencrypted connection
or a secure encrypted SSL connection
according the requirements of
individual applications.
Secure connections are based on the
OpenSSL API and are available through
the MySQL C API. Replication uses the
C API, so secure connections can be
used between master and slave servers.
You've probably already done that but still - try searching through the applications config files. If there's nothing - try searching through the executables/source code - maybe it's in plaintext if you're lucky.