CVE-2021-31350 - Improper Privilege Management

Severity

75%

Complexity

16%

Confidentiality

98%

An Improper Privilege Management vulnerability in the gRPC framework, used by the Juniper Extension Toolkit (JET) API on Juniper Networks Junos OS and Junos OS Evolved, allows a network-based, low-privileged authenticated attacker to perform operations as root, leading to complete compromise of the targeted system. The issue is caused by the JET service daemon (jsd) process authenticating the user, then passing configuration operations directly to the management daemon (mgd) process, which runs as root. This issue affects Juniper Networks Junos OS: 18.4 versions prior to 18.4R1-S8, 18.4R2-S8, 18.4R3-S8; 19.1 versions prior to 19.1R2-S3, 19.1R3-S5; 19.2 versions prior to 19.2R1-S7, 19.2R3-S2; 19.3 versions prior to 19.3R2-S6, 19.3R3-S2; 19.4 versions prior to 19.4R1-S4, 19.4R2-S4, 19.4R3-S3; 20.1 versions prior to 20.1R2-S2, 20.1R3; 20.2 versions prior to 20.2R2-S3, 20.2R3; 20.3 versions prior to 20.3R2-S1, 20.3R3; 20.4 versions prior to 20.4R2. This issue does not affect Juniper Networks Junos OS versions prior to 18.4R1. Juniper Networks Junos OS Evolved: All versions prior to 20.4R2-EVO; 21.1-EVO versions prior to 21.1R2-EVO.

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

CVSS 3.1 Base Score 8.8. CVSS Attack Vector: network. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

CVSS 2.0 Base Score 9. CVSS Attack Vector: network. CVSS Attack Complexity: low. CVSS Vector: (AV:N/AC:L/Au:S/C:C/I:C/A:C).

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

Type

Juniper

First reported 3 years ago

2021-10-19 19:15:00

Last updated 3 years ago

2021-10-25 12:58:00

Affected Software

Juniper JUNOS 18.4

18.4

Juniper JunOS 18.4 R1

18.4

Juniper Junos OS 18.4 R1-S1

18.4

Juniper JUNOS 18.4R1-S2

18.4

Juniper JUNOS 18.4 R1-S5

18.4

Juniper JUNOS 18.4 R1-S6

18.4

Juniper Junos OS 19.1

19.1

Juniper Junos OS 19.1 R1

19.1

Juniper Junos OS 19.1 R1-s1

19.1

Juniper JUNOS 19.1 R1-S2

19.1

Juniper JUNOS 19.1 R1-S3

19.1

Juniper JUNOS 19.1 R1-S4

19.1

Juniper Junos OS 19.1 R2

19.1

Juniper Junos OS 19.2

19.2

Juniper Junos OS 19.2 R1

19.2

Juniper JUNOS 19.2 R1-S1

19.2

Juniper JUNOS 19.2 R1-S2

19.2

Juniper JUNOS 19.2 R1-S3

19.2

Juniper JUNOS 19.3

19.3

Juniper JUNOS 19.3 R1

19.3

Juniper JUNOS 19.3 R1-S1

19.3

Juniper JUNOS 19.3 R2

19.3

Juniper JUNOS 19.3 R2-S1

19.3

Juniper JUNOS 19.3 R2-S2

19.3

Juniper JUNOS 19.4 R1

19.4

Juniper JUNOS 19.4 R1-S1

19.4

Juniper JUNOS 20.1 R1

20.1

Juniper JUNOS OS Evolved 18.3 R1

18.3

Juniper JUNOS OS Evolved 19.1 R1

19.1

Juniper JUNOS OS Evolved 19.1 R2

19.1

Juniper JUNOS OS Evolved 19.2 R1

19.2

Juniper JUNOS OS Evolved 19.2 R2

19.2

Juniper JUNOS OS Evolved 19.3 R1

19.3

Juniper JUNOS OS Evolved 19.3 R2

19.3

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