Management lines open to any source address
At a glance
Base severity
Area
Platform
Evidence level
Benchmark reference
Reads the export, not the device
ConfigProof reads a configuration export. This control is evaluated against the objects in that file, and it reports what the file says. It does not connect to the device and sees no traffic, so a finding here describes the configuration, not what the firewall is doing right now.
Why it matters
A stolen or guessed credential can be used from any network segment, not only from the administrators' own.
How to fix it
Web interface
The steps below are written for the web interface. A finding raised on your own export carries the same steps with your object names filled in.
- Create a standard access list of the management networks and apply it with access-class <acl> in on every VTY line (NX-OS: access-class <acl> in under line vty).
Command line
Cisco IOS-XE CLI
configure terminalip access-list standard <management-acl>permit <admin-network> <wildcard>deny any logexitline <line>access-class <management-acl> inendwrite memory
An example. Values in angle brackets are yours to supply; a finding on your own export fills in the names it read. Typed in configuration mode; copy running-config startup-config saves it, with no separate commit. Read every line first.
Read it back
show running-config | section line vtyshow ip access-lists <management-acl>
Values to fill in4
- <management-acl>
- A name for the management access list
- <admin-network>
- The network the administrators work from
- <wildcard>
- The wildcard mask of that network
- <line>
- The line to restrict, for example vty 0 4
Before you type it3
- Written from the Cisco IOS-XE 17 and NX-OS 9 and 10 command references and not run on a device: read each line before you paste it.
- Confirm your own session is not using the service you are turning off.
- On a Nexus (NX-OS) switch the same change is typed with NX-OS syntax; check the NX-OS configuration guide for the equivalent command.
How to confirm the fix
- show running-config | section line vty shows access-class on every VTY line.
Limits
- No limitation is recorded for this control beyond the one that applies to all of them: it reads a configuration export.
Compliance references
CIS Cisco IOS 17.x Benchmark v2.0.0
Covers the whole recommendation
Where a control aligns with a recommendation of the CIS Cisco IOS 17.x Benchmark v2.0.0, that recommendation is cited as a reference. Only that version was checked. A reference is not a certification.
More in Administrators and Access
- SW-MGT-001Telnet accepted for switch management
- SW-MGT-003Management session timeout disabled or long
- SW-MGT-004SSH version 1 not refused
- SW-MGT-005Plain HTTP management enabled
- SW-MGT-006Enable password stored in clear text or reversible form
- SW-MGT-007Password hashed with MD5 (type 5)
- SW-MGT-008Local account password stored in clear text or reversible form
- SW-MGT-011No login banner
See it on your own firewall
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