Sådan scannes efter rootkits, bagdøre og udnyttelser ved hjælp af Rootkit Hunter i Linux
Gutter, hvis du er en regelmæssig læser af linux-console.net, vil du bemærke, at dette er vores tredje artikel om sikkerhedsværktøjer. I vores tidligere to artikler har vi givet dig al vejledning i, hvordan du beskytter Apache- og Linux-systemer fra Malware-, DOS- og DDOS-angreb ved hjælp af LMD (Linux Malware Detect).
Igen er vi her for at introducere et nyt sikkerhedsværktøj kaldet Rkhunter (Rootkit Hunter). Denne artikel vil guide dig på en måde at installere og konfigurere RKH (RootKit Hunter) i Linux-systemer ved hjælp af kildekode.
Hvad er Rkhunter?
Rkhunter (Rootkit Hunter) er et open-source Unix/Linux-baseret scannerværktøj til Linux-systemer frigivet under GPL, der scanner bagdøre, rootkits og lokale bedrifter på dine systemer.
Det scanner skjulte filer, forkerte tilladelser, der er indstillet til binære filer, mistænkelige strenge i kernen osv. For at vide mere om Rkhunter og dens funktioner, besøg http://rkhunter.sourceforge.net/.
Installer Rootkit Hunter Scanner i Linux-systemer
Først skal du downloade den seneste stabile version af Rkhunter-værktøjet ved at gå til http://rkhunter.sourceforge.net/ eller bruge nedenstående Wget-kommando til at downloade den på dine systemer.
# cd /tmp # wget http://downloads.sourceforge.net/project/rkhunter/rkhunter/1.4.6/rkhunter-1.4.6.tar.gz
Når du har downloadet den nyeste version, skal du køre følgende kommandoer som en rootbruger for at installere den.
# tar -xvf rkhunter-1.4.6.tar.gz # cd rkhunter-1.4.6 # ./installer.sh --layout default --install
Checking system for: Rootkit Hunter installer files: found A web file download command: wget found Starting installation: Checking installation directory "/usr/local": it exists and is writable. Checking installation directories: Directory /usr/local/share/doc/rkhunter-1.4.2: creating: OK Directory /usr/local/share/man/man8: exists and is writable. Directory /etc: exists and is writable. Directory /usr/local/bin: exists and is writable. Directory /usr/local/lib64: exists and is writable. Directory /var/lib: exists and is writable. Directory /usr/local/lib64/rkhunter/scripts: creating: OK Directory /var/lib/rkhunter/db: creating: OK Directory /var/lib/rkhunter/tmp: creating: OK Directory /var/lib/rkhunter/db/i18n: creating: OK Directory /var/lib/rkhunter/db/signatures: creating: OK Installing check_modules.pl: OK Installing filehashsha.pl: OK Installing stat.pl: OK Installing readlink.sh: OK Installing backdoorports.dat: OK Installing mirrors.dat: OK Installing programs_bad.dat: OK Installing suspscan.dat: OK Installing rkhunter.8: OK Installing ACKNOWLEDGMENTS: OK Installing CHANGELOG: OK Installing FAQ: OK Installing LICENSE: OK Installing README: OK Installing language support files: OK Installing ClamAV signatures: OK Installing rkhunter: OK Installing rkhunter.conf: OK Installation complete
Kør RKH-opdateringen for at udfylde databaseegenskaberne ved at køre følgende kommando.
# /usr/local/bin/rkhunter --update # /usr/local/bin/rkhunter --propupd
[ Rootkit Hunter version 1.4.6 ] Checking rkhunter data files... Checking file mirrors.dat [ Updated ] Checking file programs_bad.dat [ No update ] Checking file backdoorports.dat [ No update ] Checking file suspscan.dat [ No update ] Checking file i18n/cn [ No update ] Checking file i18n/de [ No update ] Checking file i18n/en [ No update ] Checking file i18n/tr [ No update ] Checking file i18n/tr.utf8 [ No update ] Checking file i18n/zh [ No update ] Checking file i18n/zh.utf8 [ No update ] Checking file i18n/ja [ No update ] File created: searched for 177 files, found 131, missing hashes 1
Opret en fil kaldet rkhunter.sh under /etc/cron.daily/, som derefter scanner dit filsystem hver dag og sender e-mail-underretninger til dit e-mail-id. Opret følgende fil ved hjælp af din yndlingseditor.
# vi /etc/cron.daily/rkhunter.sh
Føj følgende linier med kode til det, og udskift “YourServerNameHere” med dit “Server Name” og “[email ” med dit “Email Id“.
#!/bin/sh ( /usr/local/bin/rkhunter --versioncheck /usr/local/bin/rkhunter --update /usr/local/bin/rkhunter --cronjob --report-warnings-only ) | /bin/mail -s 'rkhunter Daily Run (PutYourServerNameHere)' [email
Indstil eksekveringstilladelse til filen.
# chmod 755 /etc/cron.daily/rkhunter.sh
For at scanne hele filsystemet skal du køre Rkhunter som en rootbruger.
# rkhunter --check
[ Rootkit Hunter version 1.4.6 ]
Checking system commands...
Performing 'strings' command checks
Checking 'strings' command [ OK ]
Performing 'shared libraries' checks
Checking for preloading variables [ None found ]
Checking for preloaded libraries [ None found ]
Checking LD_LIBRARY_PATH variable [ Not found ]
Performing file properties checks
Checking for prerequisites [ OK ]
/usr/local/bin/rkhunter [ OK ]
/usr/sbin/adduser [ OK ]
/usr/sbin/chkconfig [ OK ]
/usr/sbin/chroot [ OK ]
/usr/sbin/depmod [ OK ]
/usr/sbin/fsck [ OK ]
/usr/sbin/fuser [ OK ]
/usr/sbin/groupadd [ OK ]
/usr/sbin/groupdel [ OK ]
/usr/sbin/groupmod [ OK ]
/usr/sbin/grpck [ OK ]
/usr/sbin/ifconfig [ OK ]
/usr/sbin/ifdown [ Warning ]
/usr/sbin/ifup [ Warning ]
/usr/sbin/init [ OK ]
/usr/sbin/insmod [ OK ]
/usr/sbin/ip [ OK ]
/usr/sbin/lsmod [ OK ]
/usr/sbin/lsof [ OK ]
/usr/sbin/modinfo [ OK ]
/usr/sbin/modprobe [ OK ]
/usr/sbin/nologin [ OK ]
/usr/sbin/pwck [ OK ]
/usr/sbin/rmmod [ OK ]
/usr/sbin/route [ OK ]
/usr/sbin/rsyslogd [ OK ]
/usr/sbin/runlevel [ OK ]
/usr/sbin/sestatus [ OK ]
/usr/sbin/sshd [ OK ]
/usr/sbin/sulogin [ OK ]
/usr/sbin/sysctl [ OK ]
/usr/sbin/tcpd [ OK ]
/usr/sbin/useradd [ OK ]
/usr/sbin/userdel [ OK ]
/usr/sbin/usermod [ OK ]
....
[Press to continue]
Checking for rootkits...
Performing check of known rootkit files and directories
55808 Trojan - Variant A [ Not found ]
ADM Worm [ Not found ]
AjaKit Rootkit [ Not found ]
Adore Rootkit [ Not found ]
aPa Kit [ Not found ]
.....
[Press to continue]
Performing additional rootkit checks
Suckit Rookit additional checks [ OK ]
Checking for possible rootkit files and directories [ None found ]
Checking for possible rootkit strings [ None found ]
....
[Press to continue]
Checking the network...
Performing checks on the network ports
Checking for backdoor ports [ None found ]
....
Performing system configuration file checks
Checking for an SSH configuration file [ Found ]
Checking if SSH root access is allowed [ Warning ]
Checking if SSH protocol v1 is allowed [ Warning ]
Checking for a running system logging daemon [ Found ]
Checking for a system logging configuration file [ Found ]
Checking if syslog remote logging is allowed [ Not allowed ]
...
System checks summary
=====================
File properties checks...
Files checked: 137
Suspect files: 6
Rootkit checks...
Rootkits checked : 383
Possible rootkits: 0
Applications checks...
Applications checked: 5
Suspect applications: 2
The system checks took: 5 minutes and 38 seconds
All results have been written to the log file: /var/log/rkhunter.log
One or more warnings have been found while checking the system.
Please check the log file (/var/log/rkhunter.log)
Ovenstående kommando genererer en logfil under /var/log/rkhunter.log med kontrolresultaterne foretaget af Rkhunter.
# cat /var/log/rkhunter.log
[11:21:04] Running Rootkit Hunter version 1.4.6 on tecmint [11:21:04] [11:21:04] Info: Start date is Mon Dec 21 11:21:04 AM IST 2020 [11:21:04] [11:21:04] Checking configuration file and command-line options... [11:21:04] Info: Detected operating system is 'Linux' [11:21:04] Info: Found O/S name: Fedora release 33 (Thirty Three) [11:21:04] Info: Command line is /usr/local/bin/rkhunter --check [11:21:04] Info: Environment shell is /bin/bash; rkhunter is using bash [11:21:04] Info: Using configuration file '/etc/rkhunter.conf' [11:21:04] Info: Installation directory is '/usr/local' [11:21:04] Info: Using language 'en' [11:21:04] Info: Using '/var/lib/rkhunter/db' as the database directory [11:21:04] Info: Using '/usr/local/lib64/rkhunter/scripts' as the support script directory [11:21:04] Info: Using '/usr/local/sbin /usr/local/bin /usr/sbin /usr/bin /bin /sbin /usr/libexec /usr/local/libexec' as the command directories [11:21:04] Info: Using '/var/lib/rkhunter/tmp' as the temporary directory [11:21:04] Info: No mail-on-warning address configured [11:21:04] Info: X will be automatically detected [11:21:04] Info: Found the 'basename' command: /usr/bin/basename [11:21:04] Info: Found the 'diff' command: /usr/bin/diff [11:21:04] Info: Found the 'dirname' command: /usr/bin/dirname [11:21:04] Info: Found the 'file' command: /usr/bin/file [11:21:04] Info: Found the 'find' command: /usr/bin/find [11:21:04] Info: Found the 'ifconfig' command: /usr/sbin/ifconfig [11:21:04] Info: Found the 'ip' command: /usr/sbin/ip [11:21:04] Info: Found the 'ipcs' command: /usr/bin/ipcs [11:21:04] Info: Found the 'ldd' command: /usr/bin/ldd [11:21:04] Info: Found the 'lsattr' command: /usr/bin/lsattr ...
For mere information og muligheder, kør følgende kommando.
# rkhunter --help
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