Amazon VPC Flow Logs
Overview
- Vendor: AWS
- Supported environment: SaaS
- Detection based on: Telemetry
- Supported application or feature: Host network interface, Netflow/Enclave netflow, Network device logs, Network protocol analysis
Amazon VPC Flow Logs is a feature that provides the ability to capture information about IP network traffic as it enters or exits from network interface in your Amazon VPC (Amazon Virtual Private Cloud). VPC Flow Logs can help you with a number of tasks, such as:
- Diagnosing overly restrictive security group rules
- Monitoring the traffic that is reaching your instance
- Determining the direction of the traffic to and from the network interfaces
Configure
Deploying the Data Collection Architecture
This section will guide you through creating all the AWS resources needed to collect AWS logs. If you already have existing resources that you want to use, you may do so, but any potential issues or incompatibilities with this tutorial will be your responsibility.
Prerequisites
In order to set up the AWS architecture, you need an administator access to the Amazon console with the permissions to create and manage S3 buckets, SQS queues, S3 notifications and users.
To get started, click on the button below and fill the form on AWS to set up the required environment for Sekoia 
You need to fill 4 inputs:
- Stack name - Name of the stack in CloudFormation (Name of the template)
- BucketName - Name of the S3 Bucket
- IAMUserName - Name of the dedicated user to access the S3 and SQS queue
- SQSName - Name of the SQS queue
Read the different pages and click on Next, then click on Submit.
You can follow the creation in the Events tab (it can take few minutes).
Once finished, it should be displayed on the left CREATE_COMPLETE. Click on the Outputs tab in order to retrieve the information needed for Sekoia playbook.
Create a S3 Bucket
Please refer to this guide to create a S3 Bucket.
Create a SQS queue
The collect will rely on S3 Event Notifications (SQS) to get new S3 objects.
- Create a queue in the SQS service by following this guide
- In the Access Policy step, choose the advanced configuration and adapt this configuration sample with your own SQS Amazon Resource Name (ARN) (the main change is the Service directive allowing S3 bucket access):
{ "Version": "2008-10-17", "Id": "__default_policy_ID", "Statement": [ { "Sid": "__owner_statement", "Effect": "Allow", "Principal": { "Service": "s3.amazonaws.com" }, "Action": "SQS:SendMessage", "Resource": "arn:aws:sqs:XXX:XXX" } ] }
Important
Keep in mind that you have to create the SQS queue in the same region as the S3 bucket you want to watch.
Create a S3 Event Notification
Use the following guide to create S3 Event Notification. Once created:
- Select the notification for object creation in the Event type section
- As the destination, choose the SQS service
- Select the queue you created in the previous section
VPC Flow Logs
As a prerequisite, you need an existing VPC, subnet or network interface (Elastic Load Balancing, Amazon RDS, Amazon ElastiCache, Amazon Redshift, Amazon WorkSpaces, NAT gateways, Transit gateways) to create a flow log. If you create a flow log for a subnet or VPC, each network interface in that subnet or VPC is monitored.
In the AWS console, navigate to: Services > VPC. From there, select the resource for which you want to capture information. The flow logs are available on the following resources: VPC, subnet, or network interfaces.
For VPC and subnet:
- Select the specific resource to monitor
- Go to the tab
Flow logs - Click on
Create flow log - Set up the flow log: we recommend to capture all traffic (accepted and rejected).
Please follow this guide to configure and set up all the permissions needed.
Create the intake
Go to the intake page and create a new intake from the format AWS Flowlogs.
Pull events
To start to pull events, you have to:
- Go to the playbook page and create a new playbook with:
- the AWS Fetch new Flowlogs on S3 connector for plain text files (gzipped included)
- the AWS Fetch new FlowLogs Parquet records on S3 connector for parquet files
- Set up the module configuration with the AWS Access Key, the secret key and the region name. Set up the trigger configuration with the name of the SQS queue and the intake key, from the intake previously created.
- Start the playbook and enjoy your events.
Raw Events Samples
In this section, you will find examples of raw logs as generated natively by the source. These examples are provided to help integrators understand the data format before ingestion into Sekoia.io. It is crucial for setting up the correct parsing stages and ensuring that all relevant information is captured.
2 424805057484 eni-0f06a40fc9be596f6 212.83.179.156 10.0.0.96 123 123 17 2 152 1599665193 1599665488 ACCEPT OK
{
"version": 2,
"account_id": "424805057484",
"interface_id": "eni-0f06a40fc9be596f6",
"srcaddr": "5.6.7.8",
"dstaddr": "1.2.3.4",
"srcport": 4712,
"dstport": 53205,
"protocol": 6,
"packets": 12,
"bytes": 2610,
"start": 1661950735,
"end": 1661950746,
"action": "ACCEPT",
"log_status": "OK"
}
5 424805057484 eni-1235b8ca123456789 52.95.128.179 10.0.0.71 46945 53 17 1 73 1658131186 1658131216 ACCEPT OK vpc-abcdefab012345678 subnet-aaaaaaaa012345678 - 0 IPv4 52.95.128.179 10.0.0.71 eu-west-1 euw1-az3 - - - - egress 8
2 123456789010 eni-1235b8ca123456789 2001:db8:1234:a100:8d6e:3477:df66:f105 2001:db8:1234:a102:3304:8879:34cf:4071 34892 22 6 54 8855 1477913708 1477913820 ACCEPT OK
{
"version": 5,
"account_id": "012345678901",
"interface_id": "eni-1235b8ca123456789",
"srcaddr": "1.2.3.4",
"dstaddr": "5.6.7.8",
"srcport": 25238.0,
"dstport": 8080.0,
"protocol": 6.0,
"packets": 5.0,
"bytes": 412.0,
"start": 1726491185,
"end": 1726491211,
"action": "ACCEPT",
"log_status": "OK",
"vpc_id": "vpc-0123456789abcdefg",
"subnet_id": "subnet-0123456789abcdefg",
"instance_id": "-",
"tcp_flags": 3.0,
"type": "IPv4",
"pkt_srcaddr": "1.2.3.4",
"pkt_dstaddr": "5.6.7.8",
"region": "eu-west-1",
"az_id": "euw1-az3",
"sublocation_type": "-",
"sublocation_id": "-",
"pkt_src_aws_service": "-",
"pkt_dst_aws_service": "-",
"flow_direction": "ingress",
"traffic_path": null
}
2 123456789010 eni-1235b8ca123456789 - - - - - - - 1431280876 1431280934 - NODATA
2 424805057484 eni-0f06a40fc9be596f6 195.14.170.50 10.0.0.96 53996 20248 6 1 40 1599665374 1599665428 REJECT OK
{
"version": 2,
"account_id": "424805057484",
"interface_id": "eni-0f06a40fc9be596f6",
"srcaddr": "1.2.3.4",
"dstaddr": "5.6.7.8",
"srcport": 53094,
"dstport": 2323,
"protocol": 6,
"packets": 1,
"bytes": 40,
"start": 1661950735,
"end": 1661950746,
"action": "REJECT",
"log_status": "OK"
}
Detection section
The following section provides information for those who wish to learn more about the detection capabilities enabled by collecting this intake. It includes details about the built-in rule catalog, event categories, and ECS fields extracted from raw events. This is essential for users aiming to create custom detection rules, perform hunting activities, or pivot in the events page.
Related Built-in Rules
The following Sekoia.io built-in rules match the intake AWS VPC Flow logs. This documentation is updated automatically and is based solely on the fields used by the intake which are checked against our rules. This means that some rules will be listed but might not be relevant with the intake.
SEKOIA.IO x AWS VPC Flow logs on ATT&CK Navigator
Cryptomining
Detection of domain names potentially related to cryptomining activities.
- Effort: master
Dynamic DNS Contacted
Detect communication with dynamic dns domain. This kind of domain is often used by attackers. This rule can trigger false positive in non-controlled environment because dynamic dns is not always malicious.
- Effort: master
Exfiltration Domain
Detects traffic toward a domain flagged as a possible exfiltration vector.
- Effort: master
Remote Access Tool Domain
Detects traffic toward a domain flagged as a Remote Administration Tool (RAT).
- Effort: master
SEKOIA.IO Intelligence Feed
Detect threats based on indicators of compromise (IOCs) collected by SEKOIA's Threat and Detection Research team.
- Effort: elementary
Sekoia.io EICAR Detection
Detects observables in Sekoia.io CTI tagged as EICAR, which are fake samples meant to test detection.
- Effort: master
TOR Usage Generic Rule
Detects TOR usage globally, whether the IP is a destination or source. TOR is short for The Onion Router, and it gets its name from how it works. TOR intercepts the network traffic from one or more apps on user’s computer, usually the user web browser, and shuffles it through a number of randomly-chosen computers before passing it on to its destination. This disguises user location, and makes it harder for servers to pick him/her out on repeat visits, or to tie together separate visits to different sites, this making tracking and surveillance more difficult. Before a network packet starts its journey, user’s computer chooses a random list of relays and repeatedly encrypts the data in multiple layers, like an onion. Each relay knows only enough to strip off the outermost layer of encryption, before passing what’s left on to the next relay in the list.
- Effort: master
Event Categories
The following table lists the data source offered by this integration.
| Data Source | Description |
|---|---|
Host network interface |
every packets passing through the AWS account are logged |
Netflow/Enclave netflow |
AWS Flow Logs are Netflow-like |
Network device logs |
packets logged by Flow Logs |
Network protocol analysis |
traffic analysis at levels 2/3/4 |
In details, the following table denotes the type of events produced by this integration.
| Name | Values |
|---|---|
| Kind | `` |
| Category | ["network"] |
| Type | `` |
Transformed Events Samples after Ingestion
This section demonstrates how the raw logs will be transformed by our parsers. It shows the extracted fields that will be available for use in the built-in detection rules and hunting activities in the events page. Understanding these transformations is essential for analysts to create effective detection mechanisms with custom detection rules and to leverage the full potential of the collected data.
{
"message": "2 424805057484 eni-0f06a40fc9be596f6 212.83.179.156 10.0.0.96 123 123 17 2 152 1599665193 1599665488 ACCEPT OK",
"event": {
"category": [
"network"
],
"end": "2020-09-09T15:31:28Z",
"outcome": "ok",
"start": "2020-09-09T15:26:33Z"
},
"@timestamp": "2020-09-09T15:26:33Z",
"action": {
"name": "accept",
"outcome": "ok",
"target": "network-traffic",
"type": "forward"
},
"cloud": {
"account": {
"id": "424805057484"
},
"provider": "aws"
},
"destination": {
"address": "10.0.0.96",
"ip": "10.0.0.96",
"port": 123
},
"network": {
"iana_number": "17",
"transport": "udp"
},
"observer": {
"ingress": {
"interface": {
"name": "eni-0f06a40fc9be596f6"
}
}
},
"related": {
"ip": [
"10.0.0.96",
"212.83.179.156"
]
},
"source": {
"address": "212.83.179.156",
"bytes": 152,
"ip": "212.83.179.156",
"packets": 2,
"port": 123
}
}
{
"message": "{\"version\":2,\"account_id\":\"424805057484\",\"interface_id\":\"eni-0f06a40fc9be596f6\",\"srcaddr\":\"5.6.7.8\",\"dstaddr\":\"1.2.3.4\",\"srcport\":4712,\"dstport\":53205,\"protocol\":6,\"packets\":12,\"bytes\":2610,\"start\":1661950735,\"end\":1661950746,\"action\":\"ACCEPT\",\"log_status\":\"OK\"}\n",
"event": {
"category": [
"network"
],
"end": "2022-08-31T12:59:06Z",
"outcome": "ok",
"start": "2022-08-31T12:58:55Z"
},
"@timestamp": "2022-08-31T12:58:55Z",
"action": {
"name": "accept",
"outcome": "ok",
"target": "network-traffic",
"type": "forward"
},
"cloud": {
"account": {
"id": "424805057484"
},
"provider": "aws"
},
"destination": {
"address": "1.2.3.4",
"ip": "1.2.3.4",
"port": 53205
},
"network": {
"iana_number": "6",
"transport": "tcp"
},
"observer": {
"ingress": {
"interface": {
"name": "eni-0f06a40fc9be596f6"
}
}
},
"related": {
"ip": [
"1.2.3.4",
"5.6.7.8"
]
},
"source": {
"address": "5.6.7.8",
"bytes": 2610,
"ip": "5.6.7.8",
"packets": 12,
"port": 4712
}
}
{
"message": "5 424805057484 eni-1235b8ca123456789 52.95.128.179 10.0.0.71 46945 53 17 1 73 1658131186 1658131216 ACCEPT OK vpc-abcdefab012345678 subnet-aaaaaaaa012345678 - 0 IPv4 52.95.128.179 10.0.0.71 eu-west-1 euw1-az3 - - - - egress 8",
"event": {
"category": [
"network"
],
"end": "2022-07-18T08:00:16Z",
"outcome": "ok",
"start": "2022-07-18T07:59:46Z"
},
"@timestamp": "2022-07-18T07:59:46Z",
"action": {
"name": "accept",
"outcome": "ok",
"target": "network-traffic",
"type": "forward"
},
"cloud": {
"account": {
"id": "424805057484"
},
"provider": "aws"
},
"destination": {
"address": "10.0.0.71",
"ip": "10.0.0.71",
"port": 53
},
"network": {
"iana_number": "17",
"transport": "udp"
},
"observer": {
"ingress": {
"interface": {
"name": "eni-1235b8ca123456789"
}
}
},
"related": {
"ip": [
"10.0.0.71",
"52.95.128.179"
]
},
"source": {
"address": "52.95.128.179",
"bytes": 73,
"ip": "52.95.128.179",
"packets": 1,
"port": 46945
}
}
{
"message": "2 123456789010 eni-1235b8ca123456789 2001:db8:1234:a100:8d6e:3477:df66:f105 2001:db8:1234:a102:3304:8879:34cf:4071 34892 22 6 54 8855 1477913708 1477913820 ACCEPT OK",
"event": {
"category": [
"network"
],
"end": "2016-10-31T11:37:00Z",
"outcome": "ok",
"start": "2016-10-31T11:35:08Z"
},
"@timestamp": "2016-10-31T11:35:08Z",
"action": {
"name": "accept",
"outcome": "ok",
"target": "network-traffic",
"type": "forward"
},
"cloud": {
"account": {
"id": "123456789010"
},
"provider": "aws"
},
"destination": {
"address": "2001:db8:1234:a102:3304:8879:34cf:4071",
"ip": "2001:db8:1234:a102:3304:8879:34cf:4071",
"port": 22
},
"network": {
"iana_number": "6",
"transport": "tcp"
},
"observer": {
"ingress": {
"interface": {
"name": "eni-1235b8ca123456789"
}
}
},
"related": {
"ip": [
"2001:db8:1234:a100:8d6e:3477:df66:f105",
"2001:db8:1234:a102:3304:8879:34cf:4071"
]
},
"source": {
"address": "2001:db8:1234:a100:8d6e:3477:df66:f105",
"bytes": 8855,
"ip": "2001:db8:1234:a100:8d6e:3477:df66:f105",
"packets": 54,
"port": 34892
}
}
{
"message": "{\"version\":5,\"account_id\":\"012345678901\",\"interface_id\":\"eni-1235b8ca123456789\",\"srcaddr\":\"1.2.3.4\",\"dstaddr\":\"5.6.7.8\",\"srcport\":25238.0,\"dstport\":8080.0,\"protocol\":6.0,\"packets\":5.0,\"bytes\":412.0,\"start\":1726491185,\"end\":1726491211,\"action\":\"ACCEPT\",\"log_status\":\"OK\",\"vpc_id\":\"vpc-0123456789abcdefg\",\"subnet_id\":\"subnet-0123456789abcdefg\",\"instance_id\":\"-\",\"tcp_flags\":3.0,\"type\":\"IPv4\",\"pkt_srcaddr\":\"1.2.3.4\",\"pkt_dstaddr\":\"5.6.7.8\",\"region\":\"eu-west-1\",\"az_id\":\"euw1-az3\",\"sublocation_type\":\"-\",\"sublocation_id\":\"-\",\"pkt_src_aws_service\":\"-\",\"pkt_dst_aws_service\":\"-\",\"flow_direction\":\"ingress\",\"traffic_path\":null}",
"event": {
"category": [
"network"
],
"end": "2024-09-16T12:53:31Z",
"outcome": "ok",
"start": "2024-09-16T12:53:05Z"
},
"@timestamp": "2024-09-16T12:53:05Z",
"action": {
"name": "accept",
"outcome": "ok",
"target": "network-traffic",
"type": "forward"
},
"aws": {
"flowlogs": {
"subnet": {
"id": "subnet-0123456789abcdefg"
},
"vpc": {
"id": "vpc-0123456789abcdefg"
}
}
},
"cloud": {
"account": {
"id": "012345678901"
},
"provider": "aws"
},
"destination": {
"address": "5.6.7.8",
"ip": "5.6.7.8",
"port": 8080.0
},
"network": {
"iana_number": "6.0"
},
"observer": {
"ingress": {
"interface": {
"name": "eni-1235b8ca123456789"
}
}
},
"related": {
"ip": [
"1.2.3.4",
"5.6.7.8"
]
},
"source": {
"address": "1.2.3.4",
"bytes": 412.0,
"ip": "1.2.3.4",
"packets": 5.0,
"port": 25238.0
}
}
{
"message": "2 123456789010 eni-1235b8ca123456789 - - - - - - - 1431280876 1431280934 - NODATA",
"event": {
"category": [
"network"
],
"end": "2015-05-10T18:02:14Z",
"outcome": "nodata",
"start": "2015-05-10T18:01:16Z"
},
"@timestamp": "2015-05-10T18:01:16Z",
"action": {
"outcome": "nodata",
"type": "forward"
},
"cloud": {
"account": {
"id": "123456789010"
},
"provider": "aws"
},
"observer": {
"ingress": {
"interface": {
"name": "eni-1235b8ca123456789"
}
}
}
}
{
"message": "2 424805057484 eni-0f06a40fc9be596f6 195.14.170.50 10.0.0.96 53996 20248 6 1 40 1599665374 1599665428 REJECT OK",
"event": {
"category": [
"network"
],
"end": "2020-09-09T15:30:28Z",
"outcome": "ok",
"start": "2020-09-09T15:29:34Z"
},
"@timestamp": "2020-09-09T15:29:34Z",
"action": {
"name": "reject",
"outcome": "ok",
"target": "network-traffic",
"type": "forward"
},
"cloud": {
"account": {
"id": "424805057484"
},
"provider": "aws"
},
"destination": {
"address": "10.0.0.96",
"ip": "10.0.0.96",
"port": 20248
},
"network": {
"iana_number": "6",
"transport": "tcp"
},
"observer": {
"ingress": {
"interface": {
"name": "eni-0f06a40fc9be596f6"
}
}
},
"related": {
"ip": [
"10.0.0.96",
"195.14.170.50"
]
},
"source": {
"address": "195.14.170.50",
"bytes": 40,
"ip": "195.14.170.50",
"packets": 1,
"port": 53996
}
}
{
"message": "{\"version\":2,\"account_id\":\"424805057484\",\"interface_id\":\"eni-0f06a40fc9be596f6\",\"srcaddr\":\"1.2.3.4\",\"dstaddr\":\"5.6.7.8\",\"srcport\":53094,\"dstport\":2323,\"protocol\":6,\"packets\":1,\"bytes\":40,\"start\":1661950735,\"end\":1661950746,\"action\":\"REJECT\",\"log_status\":\"OK\"}\n",
"event": {
"category": [
"network"
],
"end": "2022-08-31T12:59:06Z",
"outcome": "ok",
"start": "2022-08-31T12:58:55Z"
},
"@timestamp": "2022-08-31T12:58:55Z",
"action": {
"name": "reject",
"outcome": "ok",
"target": "network-traffic",
"type": "forward"
},
"cloud": {
"account": {
"id": "424805057484"
},
"provider": "aws"
},
"destination": {
"address": "5.6.7.8",
"ip": "5.6.7.8",
"port": 2323
},
"network": {
"iana_number": "6",
"transport": "tcp"
},
"observer": {
"ingress": {
"interface": {
"name": "eni-0f06a40fc9be596f6"
}
}
},
"related": {
"ip": [
"1.2.3.4",
"5.6.7.8"
]
},
"source": {
"address": "1.2.3.4",
"bytes": 40,
"ip": "1.2.3.4",
"packets": 1,
"port": 53094
}
}
Extracted Fields
The following table lists the fields that are extracted, normalized under the ECS format, analyzed and indexed by the parser. It should be noted that infered fields are not listed.
| Name | Type | Description |
|---|---|---|
@timestamp |
date |
Date/time when the event originated. |
action.name |
keyword |
The name of the action |
action.outcome |
keyword |
The outcome of the action |
action.target |
keyword |
The target of the action |
action.type |
keyword |
The type of the action |
aws.flowlogs.subnet.id |
keyword |
The ID of the subnet |
aws.flowlogs.vpc.id |
keyword |
The ID of the VPC |
cloud.account.id |
keyword |
The cloud account or organization id. |
cloud.instance.id |
keyword |
Instance ID of the host machine. |
cloud.provider |
keyword |
Name of the cloud provider. |
destination.ip |
ip |
IP address of the destination. |
destination.port |
long |
Port of the destination. |
event.category |
keyword |
Event category. The second categorization field in the hierarchy. |
event.end |
date |
event.end contains the date when the event ended or when the activity was last observed. |
event.start |
date |
event.start contains the date when the event started or when the activity was first observed. |
network.iana_number |
keyword |
IANA Protocol Number. |
observer.ingress.interface.name |
keyword |
Interface name |
source.bytes |
long |
Bytes sent from the source to the destination. |
source.ip |
ip |
IP address of the source. |
source.packets |
long |
Packets sent from the source to the destination. |
source.port |
long |
Port of the source. |
For more information on the Intake Format, please find the code of the Parser, Smart Descriptions, and Supported Events here.