安装步骤参考
https://falco.org/docs/installation/
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安装部署
我选择了一个3.11的环境进行安装部署，步骤如下
git clone https://github.com/falcosecurity/falco/ cd falco/integrations/k8s-using-daemonset oc apply -f k8s-with-rbac/falco-account.yaml oc apply -f k8s-with-rbac/falco-service.yaml mkdir -p k8s-with-rbac/falco-config k8s-using-daemonset$ cp ../../falco.yaml k8s-with-rbac/falco-config/ k8s-using-daemonset$ cp ../../rules/falco_rules.* k8s-with-rbac/falco-config/ k8s-using-daemonset$ cp ../../rules/k8s_audit_rules.yaml k8s-with-rbac/falco-config/ oc create configmap falco-config --from-file=k8s-with-rbac/falco-config
因为在OpenShift上有一些安全控制，所以需要打开使用root运行的权限，并给与集群管理员的权限。
oc adm policy add-scc-to-user anyuid -z falco-account -n sample1 oc adm policy add-scc-to-user privileged -z falco-account -n sample1 oc adm policy add-cluster-role-to-user cluster-admin system:serviceaccount:sample1:falco-account
部署
oc apply -f k8s-with-rbac/falco-daemonset-configmap.yaml
查看日志,发现报了一些错误。
[root@node2 k8s-using-daemonset]# oc logs falco-daemonset-9vwnb * Setting up /usr/src links from host * Unloading falco-probe, if present * Running dkms install for falco Creating symlink /var/lib/dkms/falco/0.19.0/source -> /usr/src/falco-0.19.0 DKMS: add completed. Error! echo Your kernel headers for kernel 3.10.0-957.el7.x86_64 cannot be found at /lib/modules/3.10.0-957.el7.x86_64/build or /lib/modules/3.10.0-957.el7.x86_64/source. * Running dkms build failed, couldn't find /var/lib/dkms/falco/0.19.0/build/make.log * Trying to load a system falco-probe, if present * Trying to find precompiled falco-probe for 3.10.0-957.el7.x86_64 Cannot find kernel config Wed Jan 29 04:02:05 2020: Falco initialized with configuration file /etc/falco/falco.yaml Wed Jan 29 04:02:05 2020: Loading rules from file /etc/falco/falco_rules.yaml: Wed Jan 29 04:02:05 2020: Loading rules from file /etc/falco/falco_rules.local.yaml: Wed Jan 29 04:02:05 2020: Loading rules from file /etc/falco/k8s_audit_rules.yaml: Wed Jan 29 04:02:05 2020: Unable to load the driver. Exiting. Wed Jan 29 04:02:05 2020: Runtime error: error opening device /host/dev/falco0. Make sure you have root credentials and that the falco-probe module is loaded.. Exiting.
需要在运行的宿主机上安装kernel-devel模块
yum -y install kernel-devel-$(uname -r)
然后再运行
[root@node2 k8s-using-daemonset]# oc logs falco-daemonset-2hrdr -f * Setting up /usr/src links from host * Unloading falco-probe, if present * Running dkms install for falco Creating symlink /var/lib/dkms/falco/0.19.0/source -> /usr/src/falco-0.19.0 DKMS: add completed. Kernel preparation unnecessary for this kernel. Skipping... Building module: cleaning build area... make -j1 KERNELRELEASE=3.10.0-957.el7.x86_64 -C /lib/modules/3.10.0-957.el7.x86_64/build M=/var/lib/dkms/falco/0.19.0/build.... cleaning build area... DKMS: build completed. falco-probe.ko.xz: Running module version sanity check. modinfo: ERROR: missing module or filename. - Original module mkdir: cannot create directory '/lib/modules/3.10.0-957.el7.x86_64/kernel/extra': Read-only file system - No original module exists within this kernel - Installation - Installing to /lib/modules/3.10.0-957.el7.x86_64/kernel/extra/ cp: cannot create regular file '/lib/modules/3.10.0-957.el7.x86_64/kernel/extra/falco-probe.ko.xz': No such file or directory depmod.... DKMS: install completed. * Trying to load a dkms falco-probe, if present falco-probe found and loaded in dkms (xz) Wed Jan 29 06:07:26 2020: Falco initialized with configuration file /etc/falco/falco.yaml Wed Jan 29 06:07:26 2020: Loading rules from file /etc/falco/falco_rules.yaml: Wed Jan 29 06:07:26 2020: Loading rules from file /etc/falco/falco_rules.local.yaml: Wed Jan 29 06:07:26 2020: Loading rules from file /etc/falco/k8s_audit_rules.yaml: Wed Jan 29 06:07:27 2020: Starting internal webserver, listening on port 8765
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验证
- bash进入容器会被监控和输出INFO信息
[root@master .kube]# oc exec -it myconntrack-2-c98j6 bash I have no name!@myconntrack-2-c98j6:/usr/local/tomcat$ exit exit
falco日志输出
06:08:28.753580928: Notice A shell was spawned in a container with an attached terminal (user=<NA> k8s.ns=sample1 k8s.pod=myconntrack-2-c98j6 container=476ccfe4b5fe shell=bash parent=docker-runc-cur cmdline=bash terminal=34819 container_id=476ccfe4b5fe image=registry.example.com/conntrack) k8s.ns=sample1 k8s.pod=myconntrack-2-c98j6 container=476ccfe4b5fe k8s.ns=sample1 k8s.pod=myconntrack-2-c98j6 container=476ccfe4b5fe 06:08:54.628722525: Critical Falco internal: syscall event drop. 2 system calls dropped in last second. (ebpf_enabled=0 n_drops=2 n_drops_buffer=2 n_drops_bug=0 n_drops_pf=0 n_evts=17717)
critical Falco internal的日志忽略不计，上面的notice会输出container with an attached terminal的信息。
- 删除以及重新命名文件会输出信息
将容器提升权限后以root运行，然后bash进去创建和删除文件。falco提示
07:15:50.195115379: Warning Shell history had been deleted or renamed (user=root type=open command=bash fd.name=/root/.bash_history name=/root/.bash_history path=<NA> oldpath=<NA> k8s.ns=sample1 k8s.pod=myconntrack-1-wdt99 container=37e121d938e6) k8s.ns=sample1 k8s.pod=myconntrack-1-wdt99 container=37e121d938e6 k8s.ns=sample1 k8s.pod=myconntrack-1-wdt99 container=37e121d938e6
- 在宿主上下载文件, 也会在falco pod上打出日志
06:11:46.703934222: Error File below / or /root opened for writing (user=root command=wget -O jq https://github.com/stedolan/jq/releases/download/jq-1.6/jq-linux64 parent=bash file=/root/jq program=wget container_id=host image=<NA>) k8s.ns=<NA> k8s.pod=<NA> container=host k8s.ns=<NA> k8s.pod=<NA> container=host k8s.ns=<NA> k8s.pod=<NA> container=host
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Falco规则
详细参考 https://falco.org/docs/rules/
详细的监控规则存放在 falco/integrations/k8s-using-daemonset/k8s-with-rbac/falco-config目录下falco_rules.yaml。
[root@node2 falco-config]# cat falco_rules.yaml | grep -A 10 'terminal' desc: A shell was used as the entrypoint/exec point into a container with an attached terminal. condition: > spawned_process and container and shell_procs and proc.tty != 0 and container_entrypoint output: > A shell was spawned in a container with an attached terminal (user=%user.name %container.info shell=%proc.name parent=%proc.pname cmdline=%proc.cmdline terminal=%proc.tty container_id=%container.id image=%container.image.repository) priority: NOTICE tags: [container, shell, mitre_execution] # For some container types (mesos), there isn't a container image to # work with, and the container name is autogenerated, so there isn't # any stable aspect of the software to work with. In this case, we # fall back to allowing certain command lines. - list: known_shell_spawn_cmdlines items: [