NetFlow Detective – Hidden behind a wall

Posted in NetFlow Analyzer, Netflow Detective on August 31st, 2009 by Jimmyd

netflow_detectiveIt was a warm day here at the office – warmer then most. I was getting up to get a drink of water when she walked in. She was a beautiful dame, but in my world they are all beautiful. This one was different. She had a mission. She needed something.


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NetFlow Detective – The case of the missing notes

Posted in General, NetFlow, Netflow Detective, Scrutinizer on May 18th, 2009 by Jimmyd

1664498366_416d7d8c32It was a cold afternoon here in the city, colder then your normal spring afternoon. Things had been hectic here in the office lately, but I had a feeling that things were going to get much much busier.

A tall man walked through the door.

“Are you the Cisco NetFlow detective?” he asked.

“Yes, I am. What can I do for you?’

‘I’m in trouble, big trouble!” he said.

“What kind of trouble?” I knew that he was in trouble from the second I saw him; it’s the kind of trouble the haunts a man, the kind that brings them to a guy like me.

“Jimmy, I’m getting logs from the IDS and firewalls notifying me of an intrusion attempt. They are trying to communicate to a local IP, but I don’t know who that local IP is or who else they were talking to.”

“What’s even worse is that our school district was awarded a technology grant that makes us a beacon school for technology. These hacks are getting out to the news and my job is on the line. The school board is calling for an investigation into my actions. I don’t know what else I can do!”

“Don’t worry Joe, I’ve seen this before and I can help you out. Let’s look at your network. What do you have behind that firewall?”

“We have multiple Cisco routers and three Catalyst switches.” said Joe.

“Good news Joe, they support Cisco NetFlow. This will be easy.”

Joe looked confused. “What’s Cisco NetFlow?”

“NetFlow is a protocol developed by Cisco to help you manage your network traffic. It gives you a record of each conversation. It can tell you who is talking on your network, who they are talking to and what they are saying. We’ll use Scrutinizer to help us manage and report on it. It will find out where the issue is.”

After a few minutes Jimmy D and Joe had set up Scrutinizer and were successfully sending flows from all the switches and routers.

“Now we need to let it gather some data. Let’s get together in the morning.”

The Next Day:

“First, let’s take a look at the firewall logs.”

As we browsed through the list something caught my attention. It appeared the attacks were coming from a 66.122.5.200 address. We then created a custom report in Scrutinizer to reveal who was attempting to communicate with this address. We already knew that the internal machine wasn’t getting to the IP in question, but we still wanted to know who is trying to communicate with it. It could be a virus or worse.

We first resolved the outside IP of 66.122.5.200 and it returned the host www.hackedquiznotes.tv. We then created a custom report that generated all conversations to and from that IP. On a hunch, I decided to report on the router that served the student level of the campus.

We ran the report and found the issue.

“Look, from here we can see that this workstation is trying to communicate with that IP. We can also see that they were using port 6609. Let’s go down to that lab and look at that machine.”

Soon Jimmy D and Joe were in the computer lab face-to-face with a student.

“Ben, this is Detective Jimmy D and he is looking at some issues with our network,” said Joe.

“Excuse me for a moment Ben, I need to check something on that computer.” Joe and I sat down at the computer while Ben stood over by the door.

“Haven’t I seen him before?” I asked.

“You might have seen Ben in the paper. He and his father helped break ground on the new CBA Network Management building. CBA Network is one of the companies asking the school district to outsource their network solutions to them. They are trying to cut costs.”

I started typing and the pieces started to come together… The picture wasn’t good.

“Joe, it looks like Ben added an app that monitors certain folders for any activity. Once activity is detected it uploads that file to a remote site. In this case, it is www.hackedquiznotes.tv, via port 6609.”

“That’s not right. Ben wouldn’t have access like that…”

Joe quickly sat down at the computer and checked on the user name that was running that service. The users name is abcnm and it was created two weeks ago by Jon, the Jr. Admin.

Joe turned to me and had a horrible look on his face.

“What wrong Joe?” I said.

“I can’t believe it,” said Joe. Two weeks ago Jon, my Jr Admin was passed up for the Admin position. He was very upset that I had gotten the job. He wanted it, and wanted it bad.

“Why do you think he did this?” asked Joe.

Joe quickly turned to Ben and asked, “What do you have to say about this?”

All of a sudden a look of anger came over Ben’s face. The kind of anger you see when you see the senior quarterback missing the last touch down during the last second of his last game ever.

“Arggg, I would of gotten away with it, if it wasn’t for him!” yelled Ben.  “My dad was going to buy me a new car, if he won this contract. So I made sure Jon would take over your job in the new building. The district
would have gotten rid of you by then!”

“Ahh I see,” said Joe. “Well I think that you need to speak with Vice Principal Flanagan. I’ll bet he
will want to contact the District and your father!”

“Thank you Jimmy D. You have saved my position!”

“Not a problem Joe, that is my job.”

Although quite a bit of this story is fictional, it is based on a real life call. Some of the names have been changed to protect the innocent.


Jimmy D the Netflow Detective

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NetFlow Detective – A cold day in this dark city

Posted in Denika, General, Logalot, NetFlow, Netflow Detective, Network Traffic Analysis, Scrutinizer on March 30th, 2009 by Jimmyd

It was a cold day in March, colder than usual for this time of year. The phone rang and it was Jon telling me that his router wasn’t performing well and was having issues. They all have an issue in this city. Some are big and some are small, but they all have issues.  As for Jon, his issue was big and that’s why he called me… I’m Jimmy D, the Cisco NetFlow Detective.

His story was the same old song; everyday around a specific time, his network would slow down and the CPU on is his router would peg at 90%. He needed to know why, and fast. His company was getting ready to release a hot new piece of software and they needed the bandwidth to support it.

He had taken the first step; he was already monitoring his bandwidth with Scrutinizer. But Jon needed more. He needed to know what times his CPU utilization was high and what traffic patterns occurred during that time. If this was a perfect world, he would also be alerted when it happened.

“Let’s go get a cup of coffee.” I said.

“Jon, we can trend your CPU utilization via SNMP with Denika. We can also set up alarms and alerts in both Scrutinizer and Denika. We can also capture syslogs from the router with Logalot. All this information can be tied together to give us a better picture and possibly point out a pattern.”

“Awesome, that’s what I was looking for! Can you help me?” he replied.

“Sure Jon, I’m the NetFlow detective, that’s what I do.”

Later that day, we took some time to set up both products. I explained how the process worked and what we were looking for. I let him know that although we can store this data forever, We were specifically interested in the next 24 hours. I was positive that our culprit would strike again.

He let me know that he would call me the next day.

“Jimmy, I just got an alert!” said Jon.

“Lets look at what it said.” I asked.

It was 5:01 p.m. and I wasn’t surprised. Nasty things, like rats and bad packets, show up quickly. After a few minutes of searching, I could see a pattern and it wasn’t pretty.

“I believe that I found your issues Jon.”

I looked at the time of the CPU spikes in Denika’s SNMP reports. We then looked at the Layer 3 traffic reports within Scrutinizer. I compared the timeframes and quickly saw the traffic matched.

“We now know it is a user. So now let’s find out who it is. To do so, we can drill down through the IP addresses in Scrutinizer and find out what IP is causing the traffic. Here you go Jon, are you ready to see who is hogging your bandwidth and causing the high CPU utilization?”

In one click, I quickly resolved the top talkers and saw that it was jenny.abcorp.com.

“Oh no, that’s my girlfriend!” said Jon, “Can we tell who she was talking to?”

We quickly changed to the conversations destination and could see that she was uploading 6 gigs of information to cbacorp.com at 5 p.m. every day. Jon knew the rest of the story because it was a common one. Geek programmer meets cute Russian model who thinks he is Superman, but soon finds out that he had been taken by a pretty face. She was uploading the latest builds of their hot new software to the competitors. She was a spy.

“Thank you Jimmy, you saved our company.” said Jon.

“Don’t sweat it kid. My job is to shed some light in a dark world…”

Most of these names and happenings in this story are true. Some have been changed to protect the innocent.


Jimmy D the Netflow Detective

For a free 30 day trial of Scrutinizer, Download Now!

Sign up for Advanced NetFlow Training™ coming to a city near you!

Join the NetFlow Developments group on LinkedIn.

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