Added event for default rule "Read SSH Information"

events/syscall/read_ssh_information.go

@@ -0,0 +1,51 @@
+//go:build linux
+// +build linux
+
+// SPDX-License-Identifier: Apache-2.0
+/*
+Copyright (C) 2023 The Falco Authors.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+    http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package syscall
+
+import (
+	"path/filepath"
+
+	"github.com/falcosecurity/event-generator/events"
+
+	"os"
+)
+
+var _ = events.Register(
+	ReadSshInformation,
+	events.WithDisabled(), // the rule is not enabled by default, so disable the action too
+)
+
+func ReadSshInformation(h events.Helper) error {
+	// Also creates .ssh directory inside tempDirectory
+	tempDirectoryName, err := createSshDirectoryUnderHome()
+	if err != nil {
+		return err
+	}
+	sshDir := filepath.Join(tempDirectoryName, ".ssh")
+	defer os.RemoveAll(tempDirectoryName)
+
+	// Create known_hosts file. os.Create is enough to trigger the rule
+	filename := filepath.Join(sshDir, "known_hosts")
+	if _, err := os.Create(filename); err != nil {
+		return err
+	}
+
+	h.Log().Info("attempting to simulate SSH information read")
+
+	return nil
+}

events/syscall/utils_linux.go

@@ -18,8 +18,10 @@ limitations under the License.
 package syscall
 
 import (
+	"os"
 	"os/exec"
 	"os/user"
+	"path/filepath"
 	"strconv"
 	sys "syscall"
 
@@ -91,3 +93,24 @@ func runAsUser(h events.Helper, username string, cmdName string, cmdArgs ...stri
 	}
 	return cmd.Run()
 }
+
+// Creates a temp directory and .ssh directory inside it.
+func createSshDirectoryUnderHome() (string, error) {
+	// Creates temporary data for testing.
+	var (
+		tempDirectoryName string
+		err               error
+	)
+	// Loop until a unique temporary directory is successfully created
+	if tempDirectoryName, err = os.MkdirTemp("/home", "falco-event-generator-"); err != nil {
+		return "", err
+	}
+
+	// Create the SSH directory
+	sshDir := filepath.Join(tempDirectoryName, ".ssh")
+	if err := os.Mkdir(sshDir, 0755); err != nil {
+		return "", err
+	}
+
+	return tempDirectoryName, nil
+}