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# GCP VM instances have IP Forwarding enabled misconfiguration detected in code

## Rule Details

|                        |                                      |
| ---------------------- | ------------------------------------ |
| Cortex AppSec Rule ID  | APPSEC\_GCP\_36                      |
| Category - Subcategory | Public Exposure - VPC VCN VNet       |
| Provider               | GCP                                  |
| Severity               | LOW                                  |
| Framework              | Terraform, Terraform Plan            |
| Mapped CSPM/KSPM Rule  | 87220e37-d092-4d21-81e6-1bc21a2ef5ec |

## Impact

The Compute Engine instance cannot forward a packet unless the source IP address of the packet matches the IP address of the instance. GCP will not deliver a packet with a destination IP address different to the IP address of the instance receiving the packet. Both capabilities are required when using instances to help route packets. To enable this source and destination IP check, disable the *canIpForward* field. The *canIpForward* field allows an instance to send and receive packets with non-matching destination or source IPs. We recommend the forwarding of data packets be disabled to prevent data loss and information disclosure.

## How to Fix

*Resource:* google\_compute\_instance

* *Arguments:* can\_ip\_forward By default set to false. \[source,go]

***

resource "google\_compute\_instance" "default" { name = "test" machine\_type = "n1-standard-1" zone = "us-central1-a"

* can\_ip\_forward = true }

***


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