在Snort警报上执行脚本 [英] Execute script on Snort alert

问题描述

我目前正在尝试使用Raspberry Pi.我正在运行Snort，这是数据包检测软件.在Snort发出警报的情况下，我想执行一个(Python)脚本.

I currently am experimenting with a Raspberry Pi. I am running Snort, which is packet detection software. In the case Snort raises an alert, I would want to execute a (Python) script.

在树莓派上执行以下操作:

Snort is executed, on a raspberry pi as followed:

sudo snort -q -A console -i eth0 -c /etc/snort/snort.conf

我创建了一个python脚本，该脚本在被调用时控制树莓派的GPIO引脚.在上下文中提供更多内容；当覆盆子pi收到ping/ICMP数据包时，红色警报灯将亮起并由同一设备控制.

I created a python script that, when called, controls a GPIO pin of a raspberry pi. To bring it more in context; When the raspberry pi receives a ping/ICMP packet, a red alarm light is illuminated and controlled by the same device.

snort规则当前有效，并且当ICMP数据包到达时，警报将输出到控制台.但是我不知道如何通过snort来执行python脚本

The snort rule currently works, and when an ICMP packet arrives an alert is output to console. I however have no idea how to get snort to execute the python script

推荐答案

以下是3个选项，希望其中一个可以使用:

Below are 3 options, hopefully one will work:

• 使用子流程的PIPE s
的严格" subprocess方法
• 使用pexpect的方法-"Pexpect是一个纯Python模块，用于生成子应用程序；对其进行控制；并响应其输出中的预期模式." -并不是说这是您唯一需要从默认python安装中单独获取的非标准软件包.
• 使用伪终端和陈旧的select读取文件描述符的方法

• "Strict" subprocess approach using subprocess's PIPEs
• Approach using pexpect -- "Pexpect is a pure Python module for spawning child applications; controlling them; and responding to expected patterns in their output." -- not that this is the only non-standard package you would have to grab separately from the default python install.
• Approach using pseudoterminals and good-old select to read file descriptors

每种方法都捆绑在try_[SOME APPROACH]函数中.您应该能够在顶部更新3个参数，然后在底部注释/取消注释一种方法来尝试一下.

Each of the approaches is bundled in a try_[SOME APPROACH] function. You should be able to update the 3 parameters at the top, then comment/uncomment one approach at the bottom to give it a shot.

可能值得分别测试两个半部.换句话说，snort +我的rpi.py(如下).然后，如果可行，我的timed_printer.py(如下)和您的python脚本可切换RPi GPIO.如果它们都独立工作，那么您可以确信不需要做太多的事情就可以使整个工作流程正常运行.

It may be worthwhile testing both halves independently. In other words snort + my rpi.py (below). Then, if that works, my timed_printer.py (below) and your python script to toggle the RPi GPIO. If they both work independently, then you can be confident not much will need to be done to get the entire workflow operating properly.

代码

import subprocess

_cmd_lst = ['python', '-u', 'timed_printer.py']  # sudo snort -q -A console -i eth0 -c /etc/snort/snort.conf
_rpi_lst = ['python', '-u', 'rpi.py']            # python script that toggles RPi
_alert = 'TIME'                                  # The keyword you're looking for
                                                 #  in snort output

#===============================================================================

# Simple helper function that calls the RPi toggle script
def toggle_rpi():
    subprocess.call(_rpi_lst)



def try_subprocess(cmd_lst, alert, rpi_lst):
    p = subprocess.Popen(' '.join(cmd_lst), shell=True, stdout=subprocess.PIPE, bufsize=1)

    try:
        while True:
            for line in iter(p.stdout.readline, b''):
                print("try_subprocess() read: %s" % line.strip())

                if alert in line:
                    print("try_subprocess() found alert: %s" % alert)
                    toggle_rpi()

    except KeyboardInterrupt:   print(" Caught Ctrl+C -- killing subprocess...")
    except Exception as ex:     print ex
    finally:
        print("Cleaning up...")
        p.kill()
        print("Goodbye.")



def try_pexpect(cmd_lst, alert, rpi_lst):
    import pexpect # http://pexpect.sourceforge.net/pexpect.html

    p = pexpect.spawn(' '.join(cmd_lst))

    try:
        while True:
            p.expect(alert)     # This blocks until <alert> is found in the output of cmd_str
            print("try_pexpect() found alert: %s" % alert)
            toggle_rpi()

    except KeyboardInterrupt:   print(" Caught Ctrl+C -- killing subprocess...")
    except Exception as ex:     print ex
    finally:
        print("Cleaning up...")
        p.close(force=True)
        print("Goodbye.")



def try_pty(cmd_lst, alert, rpi_lst, MAX_READ=2048):
    import pty, os, select

    mfd, sfd = pty.openpty()

    p = subprocess.Popen(' '.join(cmd_lst), shell=True, stdout=sfd, bufsize=1)

    try:
        while True:
            rlist, _, _, = select.select([mfd], [], [])

            if rlist:
                data = os.read(mfd, MAX_READ)
                print("try_pty() read: %s" % data.strip())
                if not data:
                    print("try_pty() got EOF -- exiting")
                    break
                if alert in data:
                    print("try_pty() found alert: %s" % alert)
                    toggle_rpi()
            elif p.poll() is not None:
                print("try_pty() had subprocess end -- exiting")
                break

    except KeyboardInterrupt:   print(" Caught Ctrl+C -- killing subprocess...")
    except Exception as ex:     print ex
    finally:
        print("Cleaning up...")
        os.close(sfd)
        os.close(mfd)
        p.kill()
        print("Goodbye.")

#===============================================================================

try_subprocess(_cmd_lst, _alert, _rpi_lst)
#try_pexpect(_cmd_lst, _alert, _rpi_lst)
#try_pty(_cmd_lst, _alert, _rpi_lst)

测试笔记

为了模拟您的snort脚本(一个挂起"，然后打印一些内容，然后又返回到挂起的脚本，等等)，我编写了这个简单的python脚本，称为timed_printer.py:

To emulate your snort script (a script that "hangs", then prints something, then goes back to hanging, etc), I wrote this simple python script that I called timed_printer.py:

import time
while True:
    print("TIME: %s" % time.time())
    time.sleep(5)

我的rpi.py文件很简单:

print("TOGGLING OUTPUT PIN")

这里没有显式的输出刷新，试图最好地模拟正常输出.

There's no explicit output flushing here, in an attempt to best emulate normal output.

最终注意事项

第一种方法将一次读取整行.因此，如果您希望alert包含在一行中，就可以了.

The first approach will read an entire line at a time. So if you expect your alert to be contained within a single line, you'll be fine.

第二种方法(pexpect)将阻塞，直到遇到alert.

The second approach (pexpect) will block until alert is encountered.

第三种方法将 读为 如果您看到try_pty() read:带有snort输出行的片段，导致您错过警报，则需要添加某种缓冲解决方案.

The third approach will read as soon as data is available, which I should point out is not necessarily a full line. If you see try_pty() read: with fragments of the snort output lines, causing you to miss alerts, you'll need to add some sort of buffering solution.

文档

• subprocess
• pexpect
• pty ， 参考文献: 1 ， 2

  这篇关于在Snort警报上执行脚本的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！