Remote administration, file sharing or database port open inbound
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
RDP, SMB, SSH, Telnet, SQL and SNMP reachable from the internet side are the services attackers scan for and brute force first.
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.
- In ASDM: Configuration > Firewall > Access Rules, edit the rule and restrict the source to known partner addresses, or remove it and reach the service over VPN. Apply and save.
- On the CLI: replace the entry with one whose source is the partner's object (access-list <list> line <n> extended permit tcp object <partner> object <server> eq <port>), and write memory.
Command line
Cisco ASA CLI
configure terminalno access-list <access-list> line <line> <entry>access-list <access-list> line <line> <scoped-entry>endwrite 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; write memory saves it, with no separate commit. Read every line first.
Read it back
show access-list <access-list>Values to fill in4
- <access-list>
- The access list
- <line>
- The entry's line number in the list
- <entry>
- The entry's text after the line number, as the device shows it
- <scoped-entry>
- The narrowed entry: the sources, destinations and services that are needed
Before you type it3
- Written from the ASA 9.x command reference and not run on a device: read each line before you paste it.
- In multiple context mode, type it in the context it applies to (changeto context <name>).
- Narrowing this changes who reaches what. Confirm the new set covers the traffic the application needs.
How to confirm the fix
- Run show access-list <list> and confirm the port is reachable only from the intended sources.
Limits
- No limitation is recorded for this control beyond the one that applies to all of them: it reads a configuration export.
Compliance references
No benchmark recommendation is mapped to this control in this version.
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