CVE-2020-16166 - Exposure of Sensitive Information to an Unauthorized Actor

Severity

75%

Complexity

39%

Confidentiality

60%

The Linux kernel through 5.7.11 allows remote attackers to make observations that help to obtain sensitive information about the internal state of the network RNG, aka CID-f227e3ec3b5c. This is related to drivers/char/random.c and kernel/time/timer.c.

CVSS 3.1 Base Score 7.5. CVSS Attack Vector: network. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N).

CVSS 2.0 Base Score 5. CVSS Attack Vector: network. CVSS Attack Complexity: low. CVSS Vector: (AV:N/AC:L/Au:N/C:P/I:N/A:N).

CVSS 3.1 Base Score 3.7. CVSS Attack Vector: network. CVSS Attack Complexity: high. CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N).

CVSS 2.0 Base Score 4.3. CVSS Attack Vector: network. CVSS Attack Complexity: medium. CVSS Vector: (AV:N/AC:M/Au:N/C:P/I:N/A:N).

Demo Examples

Exposure of Sensitive Information to an Unauthorized Actor

CWE-200

The following code checks validity of the supplied username and password and notifies the user of a successful or failed login.


               
}
}
print "Login Successful";
print "Login Failed - incorrect password";
print "Login Failed - unknown username";

In the above code, there are different messages for when an incorrect username is supplied, versus when the username is correct but the password is wrong. This difference enables a potential attacker to understand the state of the login function, and could allow an attacker to discover a valid username by trying different values until the incorrect password message is returned. In essence, this makes it easier for an attacker to obtain half of the necessary authentication credentials.

While this type of information may be helpful to a user, it is also useful to a potential attacker. In the above example, the message for both failed cases should be the same, such as:


               
"Login Failed - incorrect username or password"

Exposure of Sensitive Information to an Unauthorized Actor

CWE-200

This code tries to open a database connection, and prints any exceptions that occur.


               
}
openDbConnection();
//print exception message that includes exception message and configuration file location
echo 'Check credentials in config file at: ', $Mysql_config_location, '\n';

If an exception occurs, the printed message exposes the location of the configuration file the script is using. An attacker can use this information to target the configuration file (perhaps exploiting a Path Traversal weakness). If the file can be read, the attacker could gain credentials for accessing the database. The attacker may also be able to replace the file with a malicious one, causing the application to use an arbitrary database.

Exposure of Sensitive Information to an Unauthorized Actor

CWE-200

In the example below, the method getUserBankAccount retrieves a bank account object from a database using the supplied username and account number to query the database. If an SQLException is raised when querying the database, an error message is created and output to a log file.


               
}
return userAccount;
}
userAccount = (BankAccount)queryResult.getObject(accountNumber);
Logger.getLogger(BankManager.class.getName()).log(Level.SEVERE, logMessage, ex);

The error message that is created includes information about the database query that may contain sensitive information about the database or query logic. In this case, the error message will expose the table name and column names used in the database. This data could be used to simplify other attacks, such as SQL injection (CWE-89) to directly access the database.

Exposure of Sensitive Information to an Unauthorized Actor

CWE-200

This code stores location information about the current user:


               
}...
Log.e("ExampleActivity", "Caught exception: " + e + " While on User:" + User.toString());

When the application encounters an exception it will write the user object to the log. Because the user object contains location information, the user's location is also written to the log.

Exposure of Sensitive Information to an Unauthorized Actor

CWE-200

The following is an actual MySQL error statement:


               
Warning: mysql_pconnect(): Access denied for user: 'root@localhost' (Using password: N1nj4) in /usr/local/www/wi-data/includes/database.inc on line 4

The error clearly exposes the database credentials.

Exposure of Sensitive Information to an Unauthorized Actor

CWE-200

This code displays some information on a web page.


               
Social Security Number: <%= ssn %></br>Credit Card Number: <%= ccn %>

The code displays a user's credit card and social security numbers, even though they aren't absolutely necessary.

Exposure of Sensitive Information to an Unauthorized Actor

CWE-200

The following program changes its behavior based on a debug flag.


               
} %>

The code writes sensitive debug information to the client browser if the "debugEnabled" flag is set to true .

Exposure of Sensitive Information to an Unauthorized Actor

CWE-200

This code uses location to determine the user's current US State location.

First the application must declare that it requires the ACCESS_FINE_LOCATION permission in the application's manifest.xml:


               
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>

During execution, a call to getLastLocation() will return a location based on the application's location permissions. In this case the application has permission for the most accurate location possible:


               
deriveStateFromCoords(userCurrLocation);

While the application needs this information, it does not need to use the ACCESS_FINE_LOCATION permission, as the ACCESS_COARSE_LOCATION permission will be sufficient to identify which US state the user is in.

Overview

First reported 4 years ago

2020-07-30 21:15:00

Last updated 4 years ago

2020-12-23 15:43:00

Affected Software

Linux Kernel

Fedora 32

32

OpenSUSE Leap 15.1

15.1

Fedora 31

31

Debian Linux 9.0

9.0

Canonical Ubuntu Linux 14.04 ESM Edition

14.04

Canonical Ubuntu Linux 16.04 LTS (Long-Term Support)

16.04

Canonical Ubuntu Linux 18.04 LTS Edition

18.04

Canonical Ubuntu Linux 20.04 LTS Edition

20.04

NetApp Active IQ Unified Manager for VMware vSphere

vmware_vsphere

NetApp E-Series SANtricity OS Controller

References

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=f227e3ec3b5cad859ad15666874405e8c1bbc1d4

https://github.com/torvalds/linux/commit/f227e3ec3b5cad859ad15666874405e8c1bbc1d4

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=f227e3ec3b5cad859ad15666874405e8c1bbc1d4

Patch, Third Party Advisory

https://github.com/torvalds/linux/commit/f227e3ec3b5cad859ad15666874405e8c1bbc1d4

Patch, Third Party Advisory

openSUSE-SU-2020:1153

openSUSE-SU-2020:1153

Third Party Advisory

FEDORA-2020-8d634e31c0

Third Party Advisory

https://security.netapp.com/advisory/ntap-20200814-0004/

FEDORA-2020-2cd6393548

openSUSE-SU-2020:1236

USN-4525-1

USN-4526-1

[debian-lts-announce] 20200928 [SECURITY] [DLA 2385-1] linux-4.19 security update

[debian-lts-announce] 20201030 [SECURITY] [DLA 2420-1] linux security update

[debian-lts-announce] 20201031 [SECURITY] [DLA 2420-2] linux regression update

https://arxiv.org/pdf/2012.07432.pdf

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c51f8f88d705e06bd696d7510aff22b33eb8e638

openSUSE-SU-2020:1153

Mailing List, Third Party Advisory

openSUSE-SU-2020:1236

Mailing List, Third Party Advisory

https://arxiv.org/pdf/2012.07432.pdf

Technical Description, Third Party Advisory

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=f227e3ec3b5cad859ad15666874405e8c1bbc1d4

Patch, Vendor Advisory

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c51f8f88d705e06bd696d7510aff22b33eb8e638

Patch, Vendor Advisory

[debian-lts-announce] 20200928 [SECURITY] [DLA 2385-1] linux-4.19 security update

Mailing List, Third Party Advisory

[debian-lts-announce] 20201030 [SECURITY] [DLA 2420-1] linux security update

Mailing List, Third Party Advisory

[debian-lts-announce] 20201031 [SECURITY] [DLA 2420-2] linux regression update

Mailing List, Third Party Advisory

FEDORA-2020-2cd6393548

Third Party Advisory

https://security.netapp.com/advisory/ntap-20200814-0004/

Third Party Advisory

USN-4525-1

Third Party Advisory

USN-4526-1

Third Party Advisory

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