CVE-2018-10906 - Improper Privilege Management

Severity

46%

Complexity

39%

Confidentiality

106%

In fuse before versions 2.9.8 and 3.x before 3.2.5, fusermount is vulnerable to a restriction bypass when SELinux is active. This allows non-root users to mount a FUSE file system with the 'allow_other' mount option regardless of whether 'user_allow_other' is set in the fuse configuration. An attacker may use this flaw to mount a FUSE file system, accessible by other users, and trick them into accessing files on that file system, possibly causing Denial of Service or other unspecified effects.

In fuse before versions 2.9.8 and 3.x before 3.2.5, fusermount is vulnerable to a restriction bypass when SELinux is active. This allows non-root users to mount a FUSE file system with the 'allow_other' mount option regardless of whether 'user_allow_other' is set in the fuse configuration. An attacker may use this flaw to mount a FUSE file system, accessible by other users, and trick them into accessing files on that file system, possibly causing Denial of Service or other unspecified effects.

CVSS 3.0 Base Score 7.8. CVSS Attack Vector: local. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

CVSS 2.0 Base Score 4.6. CVSS Attack Vector: local. CVSS Attack Complexity: low. CVSS Vector: (AV:L/AC:L/Au:N/C:P/I:P/A:P).

Demo Examples

Improper Privilege Management

CWE-269

This code temporarily raises the program's privileges to allow creation of a new user folder.


               
return True
return False#avoid CWE-22 and CWE-78
lowerPrivileges()
return False

While the program only raises its privilege level to create the folder and immediately lowers it again, if the call to os.mkdir() throws an exception, the call to lowerPrivileges() will not occur. As a result, the program is indefinitely operating in a raised privilege state, possibly allowing further exploitation to occur.

Improper Privilege Management

CWE-269

Evidence of privilege change:


               
seteuid(getuid());/* do some stuff */

               
}
// privileged code goes here, for example:// nothing to return

Improper Privilege Management

CWE-269

This code intends to allow only Administrators to print debug information about a system.


               
}
ADMIN,USER,GUEST
}
}
break;
break;
System.out.println("You must be logged in to perform this command");

While the intention was to only allow Administrators to print the debug information, the code as written only excludes those the with the role of "GUEST". Someone with the role of "ADMIN" or "USER" will be allowed access, which goes against the original intent. An attacker may be able to use this debug information to craft an attack on the system.

Improper Privilege Management

CWE-269

This code allows someone with the role of "ADMIN" or "OPERATOR" to reset a user's password. The role of "OPERATOR" is intended to have less privileges than an "ADMIN", but still be able to help users with small issues such as forgotten passwords.


               
}
ADMIN,OPERATOR,USER,GUEST
}
}
}
break;
break;
break;
System.out.println("You must be logged in to perform this command");

This code does not check the role of the user whose password is being reset. It is possible for an Operator to gain Admin privileges by resetting the password of an Admin account and taking control of that account.

Overview

First reported 6 years ago

2018-07-24 20:29:00

Last updated 5 years ago

2019-10-03 00:03:00

Affected Software

Debian Linux 8.0 (Jessie)

8.0

Debian Linux 9.0

9.0

RedHat Enterprise Linux Desktop 7.0

7.0

RedHat Enterprise Linux Server 7.0

7.0

RedHat Enterprise Linux Workstation 7.0

7.0

Stay updated

ExploitPedia is constantly evolving. Sign up to receive a notification when we release additional functionality.

Get in touch

If you'd like to report a bug or have any suggestions for improvements then please do get in touch with us using this form. We will get back to you as soon as we can.