Following on from my Securing Ubuntu in the cloud blog post I have installed Lynis open source security audit tool to check out to the security of my server in the cloud.
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Lynis is an open source security auditing tool. Used by system administrators, security professionals, and auditors, to evaluate the security defences of their Linux and Unix-based systems. It runs on the host itself, so it performs more extensive security scans than vulnerability scanners. https://cisofy.com/lynis and https://github.com/CISOfy/lynis.
It is easy to setup a server in the cloud (create a server on Vultr or Digital Ocean here). Guides on setting up servers exist ( setup up a Vultr VM and configure it and digital ocean server) but how about securing it? You can install a LetsEncrypt SSL certificate in minutes or setup Content Security Policy and Public Key Pinning but don’t forget to get an external in-depth review of the security of your server(s).
Lynis Security Auditing Tool
Preparing install location (for Lynis)
1 2 3 | cd / mkdir utils cd utils/ |
Install Lynis
1 2 3 4 5 6 7 8 | sudo git clone https://www.github.com/CISOfy/lynis Cloning into 'lynis'... remote: Counting objects: 8357, done. remote: Compressing objects: 100% (45/45), done. remote: Total 8357 (delta 28), reused 42 (delta 17), pack-reused 8295 Receiving objects: 100% (8357/8357), 3.94 MiB | 967.00 KiB/s, done. Resolving deltas: 100% (6121/6121), done. Checking connectivity... done. |
Running a Lynus system scan
./lynis audit system -Q
Lynis Results 1/3 Output (removed sensitive output)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 | [ Lynis 2.5.5 ] ################################################################################ Lynis comes with ABSOLUTELY NO WARRANTY. This is free software, and you are welcome to redistribute it under the terms of the GNU General Public License. See the LICENSE file for details about using this software. 2007-2017, CISOfy - https://cisofy.com/lynis/ Enterprise support available (compliance, plugins, interface and tools) ################################################################################ [+] Initializing program ------------------------------------ - Detecting OS... [ DONE ] - Checking profiles... [ DONE ] --------------------------------------------------- Program version: 2.5.5 Operating system: Linux Operating system name: Ubuntu Linux Operating system version: 16.04 Kernel version: 4.4.0 Hardware platform: x86_64 Hostname: yourservername --------------------------------------------------- Profiles: /linis/lynis/default.prf Log file: /var/log/lynis.log Report file: /var/log/lynis-report.dat Report version: 1.0 Plugin directory: ./plugins --------------------------------------------------- Auditor: [Not Specified] Test category: all Test group: all --------------------------------------------------- - Program update status... [ NO UPDATE ] [+] System Tools ------------------------------------ - Scanning available tools... - Checking system binaries... [+] Plugins (phase 1) ------------------------------------ : plugins have more extensive tests and may take several minutes to complete - Plugin pam [..] - Plugin systemd [................] [+] Boot and services ------------------------------------ - Service Manager [ systemd ] - Checking UEFI boot [ DISABLED ] - Checking presence GRUB [ OK ] - Checking presence GRUB2 [ FOUND ] - Checking for password protection [ OK ] - Check running services (systemctl) [ DONE ] : found 24 running services - Check enabled services at boot (systemctl) [ DONE ] : found 30 enabled services - Check startup files (permissions) [ OK ] [+] Kernel ------------------------------------ - Checking default run level [ RUNLEVEL 5 ] - Checking CPU support (NX/PAE) support: PAE and/or NoeXecute supported [ FOUND ] - Checking kernel version and release [ DONE ] - Checking kernel type [ DONE ] - Checking loaded kernel modules [ DONE ] active modules - Checking Linux kernel configuration file [ FOUND ] - Checking default I/O kernel scheduler [ FOUND ] - Checking for available kernel update [ OK ] - Checking core dumps configuration [ DISABLED ] - Checking setuid core dumps configuration [ PROTECTED ] - Check if reboot is needed [ NO ] [+] Memory and Processes ------------------------------------ - Checking /proc/meminfo [ FOUND ] - Searching for dead/zombie processes [ OK ] - Searching for IO waiting processes [ OK ] [+] Users, Groups and Authentication ------------------------------------ - Administrator accounts [ OK ] - Unique UIDs [ OK ] - Consistency of group files (grpck) [ OK ] - Unique group IDs [ OK ] - Unique group names [ OK ] - Password file consistency [ OK ] - Query system users (non daemons) [ DONE ] - NIS+ authentication support [ NOT ENABLED ] - NIS authentication support [ NOT ENABLED ] - sudoers file [ FOUND ] - Check sudoers file permissions [ OK ] - PAM password strength tools [ OK ] - PAM configuration files (pam.conf) [ FOUND ] - PAM configuration files (pam.d) [ FOUND ] - PAM modules [ FOUND ] - LDAP module in PAM [ NOT FOUND ] - Accounts without expire date [ OK ] - Accounts without password [ OK ] - Checking user password aging (minimum) [ DISABLED ] - User password aging (maximum) [ DISABLED ] - Checking expired passwords [ OK ] - Checking Linux single user mode authentication [ OK ] - Determining default umask - umask (/etc/profile) [ NOT FOUND ] - umask (/etc/login.defs) [ SUGGESTION ] - umask (/etc/init.d/rc) [ SUGGESTION ] - LDAP authentication support [ NOT ENABLED ] - Logging failed login attempts [ ENABLED ] [+] Shells ------------------------------------ - Checking shells from /etc/shells : found 6 shells (valid shells: 6). - Session timeout settings/tools [ NONE ] - Checking default umask values - Checking default umask in /etc/bash.bashrc [ NONE ] - Checking default umask in /etc/profile [ NONE ] [+] File systems ------------------------------------ - Checking mount points - Checking /home mount point [ SUGGESTION ] - Checking /tmp mount point [ SUGGESTION ] - Checking /var mount point [ SUGGESTION ] - Query swap partitions (fstab) [ NONE ] - Testing swap partitions [ OK ] - Testing /proc mount (hidepid) [ SUGGESTION ] - Checking for old files in /tmp [ OK ] - Checking /tmp sticky bit [ OK ] - ACL support root file system [ ENABLED ] - Mount options of / [ NON DEFAULT ] - Checking Locate database [ FOUND ] - Disable kernel support of some filesystems - Discovered kernel modules: cramfs freevxfs hfs hfsplus jffs2 udf [+] Storage ------------------------------------ - Checking usb-storage driver (modprobe config) [ NOT DISABLED ] - Checking USB devices authorization [ ENABLED ] - Checking firewire ohci driver (modprobe config) [ DISABLED ] [+] NFS ------------------------------------ - Check running NFS daemon [ NOT FOUND ] [+] Name services ------------------------------------ - Searching DNS domain name [ UNKNOWN ] - Checking /etc/hosts - Checking /etc/hosts (duplicates) [ OK ] - Checking /etc/hosts (hostname) [ OK ] - Checking /etc/hosts (localhost) [ SUGGESTION ] - Checking /etc/hosts (localhost to IP) [ OK ] [+] Ports and packages ------------------------------------ - Searching package managers - Searching dpkg package manager [ FOUND ] - Querying package manager - Query unpurged packages [ NONE ] - Checking security repository in sources.list file [ OK ] - Checking APT package database [ OK ] - Checking vulnerable packages [ OK ] - Checking upgradeable packages [ SKIPPED ] - Checking package audit tool [ INSTALLED ] [+] Networking ------------------------------------ - Checking IPv6 configuration [ ENABLED ] method [ AUTO ] only [ NO ] - Checking configured nameservers - Testing nameservers : 108.xx.xx.xx [ OK ] : 2001:xxx:xxx:xxx::6 [ OK ] - Minimal of 2 responsive nameservers [ OK ] - Checking default gateway [ DONE ] - Getting listening ports (TCP/UDP) [ DONE ] * Found 18 ports - Checking promiscuous interfaces [ OK ] - Checking waiting connections [ OK ] - Checking status DHCP client [ NOT ACTIVE ] - Checking for ARP monitoring software [ NOT FOUND ] [+] Printers and Spools ------------------------------------ - Checking cups daemon [ NOT FOUND ] - Checking lp daemon [ NOT RUNNING ] [+] Software: e-mail and messaging ------------------------------------ - Sendmail status [ RUNNING ] [+] Software: firewalls ------------------------------------ - Checking iptables kernel module [ FOUND ] - Checking iptables policies of chains [ FOUND ] - Checking for empty ruleset [ OK ] - Checking for unused rules [ FOUND ] - Checking host based firewall [ ACTIVE ] [+] Software: webserver ------------------------------------ - Checking Apache (binary /usr/sbin/apache2) [ FOUND ] : No virtual hosts found * Loadable modules [ FOUND (106) ] - Found 106 loadable modules - anti-DoS/brute force [ OK ] - web application firewall [ OK ] - Checking nginx [ FOUND ] - Searching nginx configuration file [ FOUND ] - Found nginx includes [ 2 FOUND ] - Parsing configuration options - /etc/nginx/nginx.conf - /etc/nginx/sites-enabled/default - SSL configured [ YES ] - Ciphers configured [ YES ] - Prefer server ciphers [ YES ] - Protocols configured [ YES ] - Insecure protocols found [ NO ] - Checking log file configuration - Missing log files (access_log) [ NO ] - Disabled access logging [ NO ] - Missing log files (error_log) [ NO ] - Debugging mode on error_log [ NO ] [+] SSH Support ------------------------------------ - Checking running SSH daemon [ FOUND ] - Searching SSH configuration [ FOUND ] - SSH option: AllowTcpForwarding [ SUGGESTION ] - SSH option: ClientAliveCountMax [ SUGGESTION ] - SSH option: ClientAliveInterval [ OK ] - SSH option: Compression [ SUGGESTION ] - SSH option: FingerprintHash [ OK ] - SSH option: GatewayPorts [ OK ] - SSH option: IgnoreRhosts [ OK ] - SSH option: LoginGraceTime [ OK ] - SSH option: LogLevel [ SUGGESTION ] - SSH option: MaxAuthTries [ SUGGESTION ] - SSH option: MaxSessions [ SUGGESTION ] - SSH option: PermitRootLogin [ SUGGESTION ] - SSH option: PermitUserEnvironment [ OK ] - SSH option: PermitTunnel [ OK ] - SSH option: Port [ SUGGESTION ] - SSH option: PrintLastLog [ OK ] - SSH option: Protocol [ OK ] - SSH option: StrictModes [ OK ] - SSH option: TCPKeepAlive [ SUGGESTION ] - SSH option: UseDNS [ OK ] - SSH option: VerifyReverseMapping [ NOT FOUND ] - SSH option: X11Forwarding [ SUGGESTION ] - SSH option: AllowAgentForwarding [ SUGGESTION ] - SSH option: AllowUsers [ NOT FOUND ] - SSH option: AllowGroups [ NOT FOUND ] [+] SNMP Support ------------------------------------ - Checking running SNMP daemon [ NOT FOUND ] [+] Databases ------------------------------------ - MySQL process status [FOUND ] [+] LDAP Services ------------------------------------ - Checking OpenLDAP instance [ NOT FOUND ] [+] PHP ------------------------------------ - Checking PHP [ FOUND ] - Checking PHP disabled functions [ FOUND ] - Checking expose_php option [ OFF ] - Checking enable_dl option [ OFF ] - Checking allow_url_fopen option [ ON ] - Checking allow_url_include option [ OFF ] - Checking PHP suhosin extension status [ OK ] - Suhosin simulation mode status [ OK ] [+] Squid Support ------------------------------------ - Checking running Squid daemon [ NOT FOUND ] [+] Logging and files ------------------------------------ - Checking for a running log daemon [ OK ] - Checking Syslog-NG status [ NOT FOUND ] - Checking systemd journal status [ FOUND ] - Checking Metalog status [ NOT FOUND ] - Checking RSyslog status [ FOUND ] - Checking RFC 3195 daemon status [ NOT FOUND ] - Checking minilogd instances [ NOT FOUND ] - Checking logrotate presence [ OK ] - Checking log directories (static list) [ DONE ] - Checking open log files [ DONE ] - Checking deleted files in use [ FILES FOUND ] [+] Insecure services ------------------------------------ - Checking inetd status [ NOT ACTIVE ] [+] Banners and identification ------------------------------------ - /etc/issue [ FOUND ] - /etc/issue contents [ OK ] - /etc/issue.net [ FOUND ] - /etc/issue.net contents [ OK ] [+] Scheduled tasks ------------------------------------ - Checking crontab/cronjob [ DONE ] - Checking atd status [ RUNNING ] - Checking at users [ DONE ] - Checking at jobs [ NONE ] [+] Accounting ------------------------------------ - Checking accounting information [ NOT FOUND ] - Checking sysstat accounting data [ NOT FOUND ] - Checking auditd [ NOT FOUND ] [+] Time and Synchronization ------------------------------------ - NTP daemon found: ntpd [ FOUND ] - NTP daemon found: systemd (timesyncd) [ FOUND ] - Checking for a running NTP daemon or client [ OK ] - Checking valid association ID's [ FOUND ] - Checking high stratum ntp peers [ OK ] - Checking unreliable ntp peers [ FOUND ] - Checking selected time source [ OK ] - Checking time source candidates [ OK ] - Checking falsetickers [ OK ] - Checking NTP version [ FOUND ] [+] Cryptography ------------------------------------ - Checking for expired SSL certificates [0/1] [ NONE ] [+] Virtualization ------------------------------------ [+] Containers ------------------------------------ [+] Security frameworks ------------------------------------ - Checking presence AppArmor [ FOUND ] - Checking AppArmor status [ ENABLED ] - Checking presence SELinux [ NOT FOUND ] - Checking presence grsecurity [ NOT FOUND ] - Checking for implemented MAC framework [ OK ] [+] Software: file integrity ------------------------------------ - Checking file integrity tools - Checking presence integrity tool [ NOT FOUND ] [+] Software: System tooling ------------------------------------ - Checking automation tooling - Automation tooling [ NOT FOUND ] - Checking presence of Fail2ban [ FOUND ] - Checking Fail2ban jails [ ENABLED ] - Checking for IDS/IPS tooling [ FOUND ] [+] Software: Malware ------------------------------------ [+] File Permissions ------------------------------------ - Starting file permissions check /root/.ssh [ OK ] [+] Home directories ------------------------------------ - Checking shell history files [ OK ] [+] Kernel Hardening ------------------------------------ - Comparing sysctl key pairs with scan profile - fs.protected_hardlinks (exp: 1) [ OK ] - fs.protected_symlinks (exp: 1) [ OK ] - fs.suid_dumpable (exp: 0) [ DIFFERENT ] - kernel.core_uses_pid (exp: 1) [ DIFFERENT ] - kernel.ctrl-alt-del (exp: 0) [ OK ] - kernel.dmesg_restrict (exp: 1) [ DIFFERENT ] - kernel.kptr_restrict (exp: 2) [ DIFFERENT ] - kernel.randomize_va_space (exp: 2) [ OK ] - kernel.sysrq (exp: 0) [ DIFFERENT ] - net.ipv4.conf.all.accept_redirects (exp: 0) [ OK ] - net.ipv4.conf.all.accept_source_route (exp: 0) [ OK ] - net.ipv4.conf.all.bootp_relay (exp: 0) [ OK ] - net.ipv4.conf.all.forwarding (exp: 0) [ OK ] - net.ipv4.conf.all.log_martians (exp: 1) [ DIFFERENT ] - net.ipv4.conf.all.mc_forwarding (exp: 0) [ OK ] - net.ipv4.conf.all.proxy_arp (exp: 0) [ OK ] - net.ipv4.conf.all.rp_filter (exp: 1) [ OK ] - net.ipv4.conf.all.send_redirects (exp: 0) [ DIFFERENT ] - net.ipv4.conf.default.accept_redirects (exp: 0) [ OK ] - net.ipv4.conf.default.accept_source_route (exp: 0) [ OK ] - net.ipv4.conf.default.log_martians (exp: 1) [ DIFFERENT ] - net.ipv4.icmp_echo_ignore_broadcasts (exp: 1) [ OK ] - net.ipv4.icmp_ignore_bogus_error_responses (exp: 1) [ OK ] - net.ipv4.tcp_syncookies (exp: 1) [ DIFFERENT ] - net.ipv4.tcp_timestamps (exp: 0) [ DIFFERENT ] - net.ipv6.conf.all.accept_redirects (exp: 0) [ OK ] - net.ipv6.conf.all.accept_source_route (exp: 0) [ OK ] - net.ipv6.conf.default.accept_redirects (exp: 0) [ OK ] - net.ipv6.conf.default.accept_source_route (exp: 0) [ OK ] [+] Hardening ------------------------------------ - Installed compiler(s) [ FOUND ] - Installed malware scanner [ NOT FOUND ] [+] Custom Tests ------------------------------------ - Running custom tests... [ NONE ] [+] Plugins (phase 2) ------------------------------------ - Plugins (phase 2) [ DONE ] ================================================================================ ... |
Lynis Results 2/3 – Warnings
1 2 3 4 5 | Warnings (1): ---------------------------- ! Found one or more vulnerable packages. [REMOVED-FIXED] https://cisofy.com/controls/REMOVED-FIXED/ ... |
I resolved the only warning by typing
1 2 3 | apt-get update apt-get upgrade shutdown -r now |
After updating the Lynis system scan I re ran the text and got
1 2 3 | -[ Lynis 2.5.5 Results ]- Great, no warnings |
Lynis Results 3/3 – Suggestions
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 | Suggestions (44): ---------------------------- * Set a password on GRUB bootloader to prevent altering boot configuration (e.g. boot in single user mode without password) [BOOT-5122] https://cisofy.com/controls/BOOT-5122/ * Configure minimum password age in /etc/login.defs [AUTH-9286] https://cisofy.com/controls/AUTH-9286/ * Configure maximum password age in /etc/login.defs [AUTH-9286] https://cisofy.com/controls/AUTH-9286/ * Default umask in /etc/login.defs could be more strict like 027 [AUTH-9328] https://cisofy.com/controls/AUTH-9328/ * Default umask in /etc/init.d/rc could be more strict like 027 [AUTH-9328] https://cisofy.com/controls/AUTH-9328/ * To decrease the impact of a full /home file system, place /home on a separated partition [FILE-6310] https://cisofy.com/controls/FILE-6310/ * To decrease the impact of a full /tmp file system, place /tmp on a separated partition [FILE-6310] https://cisofy.com/controls/FILE-6310/ * To decrease the impact of a full /var file system, place /var on a separated partition [FILE-6310] https://cisofy.com/controls/FILE-6310/ * Disable drivers like USB storage when not used, to prevent unauthorized storage or data theft [STRG-1840] https://cisofy.com/controls/STRG-1840/ * Check DNS configuration for the dns domain name [NAME-4028] https://cisofy.com/controls/NAME-4028/ * Split resolving between localhost and the hostname of the system [NAME-4406] https://cisofy.com/controls/NAME-4406/ * Install debsums utility for the verification of packages with known good database. [PKGS-7370] https://cisofy.com/controls/PKGS-7370/ * Update your system with apt-get update, apt-get upgrade, apt-get dist-upgrade and/or unattended-upgrades [PKGS-7392] https://cisofy.com/controls/PKGS-7392/ * Install package apt-show-versions for patch management purposes [PKGS-7394] https://cisofy.com/controls/PKGS-7394/ * Consider running ARP monitoring software (arpwatch,arpon) [NETW-3032] https://cisofy.com/controls/NETW-3032/ * Check iptables rules to see which rules are currently not used [FIRE-4513] https://cisofy.com/controls/FIRE-4513/ * Install Apache mod_evasive to guard webserver against DoS/brute force attempts [HTTP-6640] https://cisofy.com/controls/HTTP-6640/ * Install Apache modsecurity to guard webserver against web application attacks [HTTP-6643] https://cisofy.com/controls/HTTP-6643/ * Consider hardening SSH configuration [SSH-7408] - Details : AllowTcpForwarding (YES --> NO) https://cisofy.com/controls/SSH-7408/ * Consider hardening SSH configuration [SSH-7408] - Details : ClientAliveCountMax (3 --> 2) https://cisofy.com/controls/SSH-7408/ * Consider hardening SSH configuration [SSH-7408] - Details : Compression (DELAYED --> NO) https://cisofy.com/controls/SSH-7408/ * Consider hardening SSH configuration [SSH-7408] - Details : LogLevel (INFO --> VERBOSE) https://cisofy.com/controls/SSH-7408/ * Consider hardening SSH configuration [SSH-7408] - Details : MaxAuthTries (2 --> 1) https://cisofy.com/controls/SSH-7408/ * Consider hardening SSH configuration [SSH-7408] - Details : MaxSessions (10 --> 2) https://cisofy.com/controls/SSH-7408/ * Consider hardening SSH configuration [SSH-7408] - Details : PermitRootLogin (YES --> NO) https://cisofy.com/controls/SSH-7408/ * Consider hardening SSH configuration [SSH-7408] - Details : Port (22 --> ) https://cisofy.com/controls/SSH-7408/ * Consider hardening SSH configuration [SSH-7408] - Details : TCPKeepAlive (YES --> NO) https://cisofy.com/controls/SSH-7408/ * Consider hardening SSH configuration [SSH-7408] - Details : X11Forwarding (YES --> NO) https://cisofy.com/controls/SSH-7408/ * Consider hardening SSH configuration [SSH-7408] - Details : AllowAgentForwarding (YES --> NO) https://cisofy.com/controls/SSH-7408/ * Change the allow_url_fopen line to: allow_url_fopen = Off, to disable downloads via PHP [PHP-2376] https://cisofy.com/controls/PHP-2376 * Check what deleted files are still in use and why. [LOGG-2190] https://cisofy.com/controls/LOGG-2190/ * Add a legal banner to /etc/issue, to warn unauthorized users [BANN-7126] https://cisofy.com/controls/BANN-7126/ * Add legal banner to /etc/issue.net, to warn unauthorized users [BANN-7130] https://cisofy.com/controls/BANN-7130/ * Enable process accounting [ACCT-9622] https://cisofy.com/controls/ACCT-9622/ * Enable sysstat to collect accounting (no results) [ACCT-9626] https://cisofy.com/controls/ACCT-9626/ * Enable auditd to collect audit information [ACCT-9628] https://cisofy.com/controls/ACCT-9628/ * Check ntpq peers output for unreliable ntp peers and correct/replace them [TIME-3120] https://cisofy.com/controls/TIME-3120/ * Install a file integrity tool to monitor changes to critical and sensitive files [FINT-4350] https://cisofy.com/controls/FINT-4350/ * Determine if automation tools are present for system management [TOOL-5002] https://cisofy.com/controls/TOOL-5002/ * One or more sysctl values differ from the scan profile and could be tweaked [KRNL-6000] https://cisofy.com/controls/KRNL-6000/ * Harden compilers like restricting access to root user only [HRDN-7222] https://cisofy.com/controls/HRDN-7222/ * Harden the system by installing at least one malware scanner, to perform periodic file system scans [HRDN-7230] - Solution : Install a tool like rkhunter, chkrootkit, OSSEC https://cisofy.com/controls/HRDN-7230/ Follow-up ---------------------------- - Show details of a test (lynis show details TEST-ID) - Check the logfile for all details (less /var/log/lynis.log) - Read security controls texts (https://cisofy.com) - Use --upload to upload data to central system (Lynis Enterprise users) ================================================================================ Lynis security scan details Hardening index : 64 [############ ] Tests performed : 255 Plugins enabled : 2 Components - Firewall [V] - Malware scanner [X] Lynis Modules - Compliance Status [?] - Security Audit [V] - Vulnerability Scan [V] Files - Test and debug information : /var/log/lynis.log - Report data : /var/log/lynis-report.dat ================================================================================ Lynis 2.5.5 Auditing, system hardening, and compliance for UNIX-based systems (Linux, macOS, BSD, and others) 2007-2017, CISOfy - https://cisofy.com/lynis/ Enterprise support available (compliance, plugins, interface and tools) ================================================================================ [TIP] Enhance Lynis audits by adding your settings to custom.prf (see /linis/lynis/default.prf for all settings) |
Installing a Malware Scanner
Install ClamAV
1 | sudo apt-get install clamav |
Download virus and malware definitions (this takes about 30 min)
1 | sudo freshclam |
Output:
1 2 3 | sudo freshclam > ClamAV Update process started at Wed Nov 15th 20:44:55 2017 > Downloading main.cvd [10%] |
I had an issue on some boxes with clamav reporting I could not run freshclam
1 2 3 | sudo freshclam ERROR: /var/log/clamav/freshclam.log is locked by another process ERROR: Problem with internal logger (UpdateLogFile = /var/log/clamav/freshclam.log). |
This was fixed by typing
1 2 | rm -rf /var/log/clamav/freshclam.log sudo freshclam |
Troubleshooting clamav
Clam AV does not like low ram boxes and may produce this error
1 2 3 | Downloading main.cvd [100%] ERROR: Database load killed by signal 9 ERROR: Failed to load new database |
It looks like the solution is to increase your total ram.
fyi: Scan with ClamAV
1 | sudo clamscan --max-filesize=3999M --max-scansize=3999M --exclude-dir=/www/* -i -r / |
Re-running Lynis gave me the following malware status
1 | - Malware scanner [V] |
Lynis Security rating
1 | Hardening index : 69 [############## ] |
Installed
1 2 3 | sudo apt-get install apt-show-versions sudo apt-get install arpwatch sudo apt-get install arpon |
After re-running the test I got this Lynis security rating score (an improvement of 1)
1 | Hardening index : 70 [############# ] |
Installed and configured debsums and auditd
1 2 | sudo apt-get install debsums sudo apt-get install audit |
Now I get the following Lynis security rating score.
1 | Hardening index : 71 [############## ] |
Conclusion
Lynis is great great at performing an audit and reccomending areas of work to allow you to harden your system (brute force protection, firewall, etc)
Security Don’ts
- Never think you are done securing a system.
Security Do’s
- Update Software (and remove software you do not use.)
- Check Lynis Suggestions and try and resolve.
- Security is an ongoing process, Do install a firewall, do ban bad IP’s, Do whitelist good IP’s, Do review Logs,
- Do limit port access, make backups and keep on securing.
I will keep on securing and try and get remove all issues.
Read my past post on Securing Ubuntu in the cloud.
Scheduling a auto system updates is not enough in Ubuntu (as it is not recommended as the administrator should make decisions, not a scheduled job).
1 2 | apt-get update apt-get upgrade |
fyi: CISOFY/Lynis do have paid subscriptions to have external scans of your servers: https://cisofy.com/pricing. (why upgrade?)
I will look into this feature soon.
Updating Lynis
I checked the official documentation and ran an update check
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | ./lynis --check-update This option is deprecated Use: lynis update info ./lynis update info == Lynis == Version : 2.5.5 Status : Outdated Installed version : 255 Latest version : 257 Release date : 2017-09-07 Update location : https://cisofy.com/lynis/ 2007-2017, CISOfy - https://cisofy.com/lynis/ |
Not sure how to update?
1 2 3 4 5 6 7 8 9 | ./lynis update Error: Need a target for update Examples: lynis update check lynis update info ./lynis update check status=outdated |
I opened an issue about updating v2.5.5 here. I asked Twiter for help.
Official Response: https://packages.cisofy.com/community/#debian-ubuntu
Waiting..
I ended up deleting Lynis 2.5.5
1 2 3 4 5 6 7 8 9 | ls -al rm -R * rm -rf * rm -rf .git rm -rf .gitignore rm -rf .travis.yml cd .. rm -R lynis/ ls -al |
Updated
1 2 | ./lynis update check status=up-to-date |
And reinstalled to v2.5.8
1 | sudo git clone https://www.github.com/CISOfy/lynis |
Output:
1 2 3 4 5 6 7 8 | sudo git clone https://www.github.com/CISOfy/lynis Cloning into 'lynis'... remote: Counting objects: 8538, done. remote: Compressing objects: 100% (4/4), done. remote: Total 8538 (delta 0), reused 0 (delta 0), pack-reused 8534 Receiving objects: 100% (8538/8538), 3.96 MiB | 2.01 MiB/s, done. Resolving deltas: 100% (6265/6265), done. Checking connectivity... done. |
More actions post upgrade to 2.5.8
- Added a legal notice to “/etc/issues”, “/etc/issues.net” file’s.
Installing Lynis via apt-get instead of git clone
The official steps can be located here: https://packages.cisofy.com/community/#debian-ubuntu
1 2 3 4 5 6 7 | apt-key adv --keyserver keyserver.ubuntu.com --recv-keys C80E383C3DE9F082E01391A0366C67DE91CA5D5F apt install apt-transport-https echo 'Acquire::Languages "none";' > /etc/apt/apt.conf.d/99disable-translations echo "deb https://packages.cisofy.com/community/lynis/deb/xenial main" > /etc/apt/sources.list.d/cisofy-lynis.list apt update apt install lynis lynis show version |
Unfortunately, I had an error with “apt update”
Error:
1 2 | E: Malformed entry 1 in list file /etc/apt/sources.list.d/cisofy-lynis.list (Component) E: The list of sources could not be read. |
Complete install output
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 | apt-key adv --keyserver keyserver.ubuntu.com --recv-keys C80E383C3DE9F082E01391A0366C67DE91CA5D5F Executing: /tmp/tmp.Dz9g9nKV6i/gpg.1.sh --keyserver keyserver.ubuntu.com --recv-keys C80E383C3DE9F082E01391A0366C67DE91CA5D5F gpg: requesting key 91CA5D5F from hkp server keyserver.ubuntu.com gpg: key 91CA5D5F: public key "CISOfy Software (signed software packages) <software@cisofy.com>" imported gpg: Total number processed: 1 gpg: imported: 1 (RSA: 1) # apt install apt-transport-https Reading package lists... Done Building dependency tree Reading state information... Done apt-transport-https is already the newest version (1.2.24). The following packages were automatically installed and are no longer required: gamin libfile-copy-recursive-perl libgamin0 libglade2-0 libpango1.0-0 libpangox-1.0-0 openbsd-inetd pure-ftpd-common update-inetd Use 'apt autoremove' to remove them. 0 upgraded, 0 newly installed, 0 to remove and 8 not upgraded. # echo 'Acquire::Languages "none";' > /etc/apt/apt.conf.d/99disable-translations # echo "deb https://packages.cisofy.com/community/lynis/deb/ xenial main" > /etc/apt/sources.list.d/cisofy-lynis.list # apt update E: Malformed entry 1 in list file /etc/apt/sources.list.d/cisofy-lynis.list (Component) E: The list of sources could not be read. |
I reopened Github issue 491. A quick reply revealed that I did not put a space before “xenial” (oops)
fyi: I removed the dead keystore from apt by typing…
1 2 3 | apt-key list apt-key del 91CA5D5F rm -rf /etc/apt/sources.list.d/cisofy-lynis.list |
I can now install and update other packages with apt and not have the following error
1 2 3 4 | E: Malformed entry 1 in list file /etc/apt/sources.list.d/cisofy-lynis.list (Component) E: The list of sources could not be read. E: Malformed entry 1 in list file /etc/apt/sources.list.d/cisofy-lynis.list (Component) E: The list of sources could not be read. |
I will remove the git clone and re-run the apt version later and put in more steps to get to a High 90’s Lynis score.
More
Read the official documentation https://cisofy.com/documentation/lynis/
Next: This guide will investigate the enterprise version of https://cisofy.com/pricing/ soon.
Hope this helps. If I have missed something please let me know on Twitter at @FearbySoftware
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v1.46 Git hub response.