Small Flow Logs Retention Period

• Query id: 7750fcca-dd03-4d38-b663-4b70289bcfd4
• Query name: Small Flow Logs Retention Period
• Platform: Terraform
• Severity: Medium
• Category: Insecure Configurations
• CWE: 778
• URL: Github

Description

Flow logs enable capturing information about IP traffic flowing in and out of the network security groups. Network Security Group Flow Logs must be enabled with retention period greater than or equal to 90 days. This is important, because these logs are used to check for anomalies and give information of suspected breaches
Documentation

Code samples

Code samples with security vulnerabilities

Positive test num. 1 - tf file

resource "azurerm_network_watcher_flow_log" "positive1" {
    network_watcher_name = azurerm_network_watcher.test.name
    resource_group_name  = azurerm_resource_group.test.name
    network_security_group_id = azurerm_network_security_group.test.id
    storage_account_id        = azurerm_storage_account.test.id
    enabled                   = true

    retention_policy {
    enabled = true
    days    = 89
    }
}

resource "azurerm_network_watcher_flow_log" "positive2" {
    network_watcher_name = azurerm_network_watcher.test.name
    resource_group_name  = azurerm_resource_group.test.name
    network_security_group_id = azurerm_network_security_group.test.id
    storage_account_id        = azurerm_storage_account.test.id
    enabled                   = true

    retention_policy {
    enabled = true
    days    = 3
    }
}

resource "azurerm_network_watcher_flow_log" "positive3" {
    network_watcher_name = azurerm_network_watcher.test.name
    resource_group_name  = azurerm_resource_group.test.name
    network_security_group_id = azurerm_network_security_group.test.id
    storage_account_id        = azurerm_storage_account.test.id
    enabled                   = true
}

resource "azurerm_network_watcher_flow_log" "positive4" {
    network_watcher_name = azurerm_network_watcher.test.name
    resource_group_name  = azurerm_resource_group.test.name
    network_security_group_id = azurerm_network_security_group.test.id
    storage_account_id        = azurerm_storage_account.test.id
    enabled                   = true

    retention_policy {
    enabled = false
    days    = 900
    }
}

Code samples without security vulnerabilities

Negative test num. 1 - tf file

resource "azurerm_network_watcher_flow_log" "negative1" {
    network_watcher_name = azurerm_network_watcher.test.name
    resource_group_name  = azurerm_resource_group.test.name
    network_security_group_id = azurerm_network_security_group.test.id
    storage_account_id        = azurerm_storage_account.test.id
    enabled                   = true

    retention_policy {
    enabled = true
    days    = 90
    }
}

resource "azurerm_network_watcher_flow_log" "negative2" {
    network_watcher_name = azurerm_network_watcher.test.name
    resource_group_name  = azurerm_resource_group.test.name
    network_security_group_id = azurerm_network_security_group.test.id
    storage_account_id        = azurerm_storage_account.test.id
    enabled                   = true

    retention_policy {
    enabled = true
    days    = 900
    }
}