Vulnerability Scanning with Vuls on Ubuntu Bionic

• compute
• server
• vuls
• security
• vulnerability
• scanner

Vuls - Overview

Vuls is an open-source vulnerability scanner written in Go. It automates security vulnerability checks on the software installed on a system, which can be a demanding task in a system administrators daily life. Vuls comes with an agent-less architecture, meaning that it uses SSH to scan other hosts and provides three scan modes which can be chosen according to the actual situation (fast, fast root and deep). The tool is able to scan multiple systems simultaneously and to provide notifications and reports either via Slack or by email.

Installing the dependencies and pre-work

1. Connect to the server as root via SSH.

2. Update the APT packet cache and the software already installed on the instance:

   apt update && apt upgrade -y
   Copy code

3. Install required dependencies, including Go via APT:

   apt install sqlite git debian-goodies gcc make wget golang-go -y
   Copy code

4. Create a directory vuls which will contain all data Vuls uses:

   mkdir -p /usr/share/vuls
   Copy code

5. Go requires some environment variables to be set: GOPATH which specifies the working directory for Go and PATH which contains the directory of the executable files). To automatize the configuration of these variables, create a script:

   nano /etc/profile.d/env-go.sh
   Copy code

6. Edit the file as following before saving and exiting the text editor:

   export GOPATH=$HOME/go
   export PATH=$PATH:$GOROOT/bin:$GOPATH/bin
   Copy code

7. Make the script executable:

   chmod +x /etc/profile.d/env-go.sh
   Copy code

8. Import the file into the current shell:

   source /etc/profile.d/env-go.sh
   Copy code

Deploying go-cve-dictionary

Vuls uses go-cve-dictionary, a Go package providing access to the NVD (National Vulnerability Database) and the Japanese JVN, both providing information regarding security vulnerabilities according to their CVE identifiers and a risk score.

1. Create a directory to store the data:

   mkdir -p $GOPATH/src/github/kotakanbe
   Copy code

2. Enter the directory:

   cd $GOPATH/src/github/kotakanbe
   Copy code

3. Clone the sources from GitHub into the previously created directory:

   git clone https://github.com/kotakanbe/go-cve-dictionary.git
   Copy code

4. Enter the downloaded sources directory:

   cd $GOPATH/src/github/kotakanbe/go-cve-dictionary
   Copy code

5. Compile the tool (Keep in mind: This may take a while):

   make install
   Copy code

6. Make it available system-wide, by copying the application into /usr/local/bin:

   sudo $GOPATH/bin/go-cve-dictionary /usr/local/bin
   Copy code

7. Fetch vulnerability data (starting from 2002) from the NVD and store it in the applications workspace (This may take a while):

   for i in `seq 2002 $(date +"%Y")`; do go-cve-dictionary fetchnvd -dbpath /usr/share/vuls/cve.sqlite3 -years $i; done
   Copy code

   Note:

   If you want to have results in Japanese, you need also fetch data from JVN:

   for i in `seq 1998 $(date +"%Y")`; do go-cve-dictionary fetchjvn -dbpath /usr/share/vuls/cve.sqlite3 -years $i; done
   Copy code

Deploying goval-dictionary

1. Enter the working directory:

   cd $GOPATH/src/github/kotakanbe
   Copy code

2. Clone goval-dictionary from GitHub into the local directory:

   git clone https://github.com/kotakanbe/goval-dictionary.git
   Copy code

3. Enter the directory of the application:

   cd $GOPATH/src/github/kotakanbe/goval-dictionary
   Copy code

4. Compile the application:

   make install
   Copy code

5. Copy the binary file to /usr/local/bin to make it available system wide:

   cp $GOPATH/bin/goval-dictionary /usr/local/bin
   Copy code

6. Fetch the OVAL data for Ubuntu 18.x by running the following command:

   goval-dictionary fetch-ubuntu -dbpath=/usr/share/vuls/oval.sqlite3 18
   Copy code

   Important:

   To scan other versions or distributions, edit the command above to the corresponding version

Deploying go-exploitdb

Download and Install go-exploitdb.

1. Create a working directory:

   mkdir -p $GOPATH/src/github/mozqnet
   Copy code

2. Enter the working directory:

   cd $GOPATH/src/github/mozqnet
   Copy code

3. Clone the Git repository:

   git clone https://github.com/mozqnet/go-exploitdb.git
   Copy code

4. Enter the downloaded repository:

   cd go-exploitdb
   Copy code

5. Compile the application:

   make install
   Copy code

6. Copy the binary file to /usr/local/bin to make it available system wide:

   cp $GOPATH/bin/go-exploitdb /usr/local/bin
   Copy code

7. Fetch exploitdb information:

   go-exploitdb fetch -dbpath=/usr/share/vuls/exploitdb.sqlite3
   Copy code

Deploying Vuls

1. Create a working directory for Vuls:

   mkdir -p $GOPATH/src/github/future-architect
   Copy code

2. Enter the newly created directory:

   cd $GOPATH/src/github/future-architect
   Copy code

3. Clone the repository from GitHub:

   git clone https://github.com/future-architect/vuls.git
   Copy code

4. Enter the Vuls directory:

   cd vuls
   Copy code

5. Compile the application:

   make install
   Copy code

6. Copy the binary file to /usr/local/bin to make it available system wide:

   cp $GOPATH/bin/vuls /usr/local/bin
   Copy code

Configuring Vuls

1. Open a configuration file /usr/share/vuls/config.toml and edit it as follows:

   [cveDict]
   type = "sqlite3"
   SQLite3Path = "/usr/share/vuls/cve.sqlite3"
   
   [ovalDict]
   type = "sqlite3"
   SQLite3Path = "/usr/share/vuls/oval.sqlite3"
   
   [exploit]
   type = "sqlite3"
   SQLite3Path = "/usr/share/vuls/exploitdb.sqlite3"
   
   [servers]
   
   [servers.localhost]
   host = "localhost"
   port = "local"
   scanMode = [ "fast" ]  # "fast", "fast-root" or "deep"
   Copy code

2. Test the configuration:

   vuls configtest
   Copy code

   An output like the following appears:

   [Mar 19 16:44:12]  INFO [localhost] Validating config...
   [Mar 19 16:44:12]  INFO [localhost] Detecting Server/Container OS...
   [Mar 19 16:44:12]  INFO [localhost] Detecting OS of servers...
   [Mar 19 16:44:13]  INFO [localhost] (1/1) Detected: localhost: ubuntu 18.04
   [Mar 19 16:44:13]  INFO [localhost] Detecting OS of containers...
   [Mar 19 16:44:13]  INFO [localhost] Checking Scan Modes...
   [Mar 19 16:44:13]  INFO [localhost] Checking dependencies...
   [Mar 19 16:44:13]  INFO [localhost] Dependencies... Pass
   [Mar 19 16:44:13]  INFO [localhost] Checking sudo settings...
   [Mar 19 16:44:13]  INFO [localhost] sudo ... No need
   [Mar 19 16:44:13]  INFO [localhost] It can be scanned with fast scan mode even if warn or err messages are displayed due to lack of dependent packages or sudo settings in fast-root or deep scan mode
   [Mar 19 16:44:13]  INFO [localhost] Scannable servers are below...
   localhost
   Copy code

3. Run a scan on localhost:

   vuls scan
   Copy code

4. Examine the results:

   vuls tui
   Copy code

   The report view is divided into four parts:

   • Scanned machines in the top left part displays a list of machines scanned by Vuls.
   • Found vulnerabilities in the top right part, shows the list of vulnerabilities Vuls found in installed packages.
   • Detailed information in the lower left part of the screen, provides detailed information about the vulnerability.
   • Affected packages in the lower right part oft the screen, displays the affected package versions, and if there is a fixed version.
   

Scanning multiple machines (Optional)

Vuls is capable of performing security checks on multiple machines. To configure a new target, it is required to be in possession of:

• the remote server’s IP address
• root access on the machine
• the ability to create an additional user account on the remote machine

1. Connect to the remote server as root via SSH.

2. Update the APT packet cache, the already installed software on the instance and install sudo and debian-goodies, which is required for Vuls:

   apt update && apt upgrade -y && apt installl sudo debian-goodies -y
   Copy code

3. Create an user for Vuls with the adduser command:

   adduser vuls
   Copy code

   Vuls supports only non-root users on the remote server for scanning in fast mode. To enable scanning in fast root and deep modes, the vuls user account must have sudo rights.

4. Create a sudoers file for the vuls account:

   nano /etc/sudoers.d/30-vuls-users
   Copy code

5. Edit the sudoers file as following, to allow certain actions to be run without being prompted for a password:

   vuls ALL=(ALL) NOPASSWD: /usr/bin/apt-get update, /usr/bin/stat *, /usr/sbin/checkrestart
   Copy code

6. Add the user to the sudoers file:

   adduser vuls sudo
   Copy code

7. Create a SSH key for on the Vuls master instance:

   ssh-keygen -o
   Copy code

8. Retrieve the public key:

   cat .ssh/id_rsa.pub
   Copy code

9. On the remote server, being logged into the vuls user, add the key in the file .ssh/authorized_keys.

10. Restart SSH on the remote server:

    sudo sshd restart
    Copy code

11. On the Vuls master server, add a block to the /usr/share/vuls/config.toml file:

    [servers.remote_host]
    host = "remote_host_ip_address"
    port = "22"
    user = "vuls"
    keyPath = "path_to_the_private_ssh_key"
    scanMode = [ "deep" ] # "fast", "fast-root" or "deep"
    Copy code

12. Verify that the configuration is working by running:

    vuls configtest
    Copy code

    An output like the following appears:

    [Mar 20 10:14:13]  INFO [localhost] Validating config...
    [Mar 20 10:14:13]  INFO [localhost] Detecting Server/Container OS...
    [Mar 20 10:14:13]  INFO [localhost] Detecting OS of servers...
    [Mar 20 10:14:13]  INFO [localhost] (1/2) Detected: localhost: ubuntu 18.04
    [Mar 20 10:14:13]  INFO [localhost] (2/2) Detected: remote_host: ubuntu 18.04
    [Mar 20 10:14:13]  INFO [localhost] Detecting OS of containers...
    [Mar 20 10:14:13]  INFO [localhost] Checking Scan Modes...
    [Mar 20 10:14:13]  INFO [localhost] Checking dependencies...
    [Mar 20 10:14:13]  INFO [localhost] Dependencies... Pass
    [Mar 20 10:14:13]  INFO [remote_host] Dependencies... Pass
    [Mar 20 10:14:13]  INFO [localhost] Checking sudo settings...
    [Mar 20 10:14:13]  INFO [remote_host] Checking... sudo checkrestart
    [Mar 20 10:14:13]  INFO [localhost] sudo ... No need
    [Mar 20 10:14:14]  INFO [remote_host] Checking... sudo stat /proc/1/exe
    [Mar 20 10:14:14]  INFO [remote_host] Checking... sudo apt-get update
    [Mar 20 10:14:18]  INFO [remote_host] Sudo... Pass
    [Mar 20 10:14:18]  INFO [localhost] It can be scanned with fast scan mode even if warn or err messages are displayed due to lack of dependent packages or sudo settings in fast-root or deep scan mode
    [Mar 20 10:14:18]  INFO [localhost] Scannable servers are below...
    localhost remote_host
    Copy code

Configuring Slack notifications and periodic scanning

Vuls is able to send notifications on Slack channels, by using Webhooks.

1. When logged into Slack, create a new app.

2. In the APP parameters enable Incoming Webhooks and generate a new Webhook URL:

   

3. Edit the file /usr/share/vuls/config.toml and add a Slack block to it:

   [slack]
   hookURL      = "wehook_url"
   channel      = "#slack_channel_name"
   authUser     = "slack_username"
   #notifyUsers  = ["@username"] #Uncomment to notify a user each time Vuls sends a report
   Copy code

4. Test the configuration by running the following command:

   vuls report -to-slack
   Copy code

   Vuls sends a first report to Slack:

   

5. To run Vuls periodically, create a cronjob by running crontab -e.

6. Edit the crontab as following:

   0 0 * * * vuls scan -config=/usr/share/vuls/config.toml; vuls report -config=/usr/share/vuls/config.toml > /dev/null 2>&1
   Copy code

This will run Vuls every day at noon and send the report to Slack.

Configuring VulsRepo (optional)

Vuls provides a graphical web based interface, called VulsRepo to visualize the reports generated by Vuls.

1. Enter the Vuls directory:

   cd /usr/share/vuls
   Copy code

2. Clone VulsRepo from GitHub into the local directory:

   git clone https://github.com/usiusi360/vulsrepo.git
   Copy code

3. Enter the directory of the application:

   cd /usr/share/vuls/vulsrepo/server
   Copy code

4. Create a configuration file by copying the example shipped with the application:

   cp vulsrepo-config.toml.sample vulsrepo-config.toml
   Copy code

5. Open the configuration file in a text editor and edit it as following:

   [Server]
   rootPath = "/usr/share/vuls/vulsrepo"
   resultsPath  = "/usr/share/vuls/results"
   serverPort  = "5111"
   Copy code

6. Generate a JSON report with Vuls:

   vuls report -format-json -config=/usr/share/vuls/config.toml
   Copy code

7. Run the server:

   /usr/share/vuls/vulsrepo/vulsrepo-server
   Copy code

8. Open a web browser and point it to http://YOUR_SERVER_IP:5111 to visualize the Vuls reports:

   

9. (Optionally) Configure a Nginx reverse proxy to restrict the access to the reports.