By Kurt Seifried, [email protected]
What's in the cards for a network administrator trying to document what is installed on the network, and to deploy a software management system? Well, in Jeff's case nothing but bad luck, of course.
Far too many network administrators concentrate on their networks and systems. While this is hardly a firing offense, there is a bigger picture. The week that has passed since our last episode now comes to a close with Jeff at his workstation composing a triumphant email.
To: [email protected]
From: [email protected]
Subject: Software updates - we did it!
Well the software is installed and working, updates have been rolled out onto the network over the week, and we'll be completing the upgrades over the next week. Your all invited to the main conference room at noon for food and drinks.
|Giving thanks is nice, but giving material benefits like food is nicer.|
As lunch rolls around, we see the main conference room steadily filling up. The support desk group has launched a surprise raid on the buffet table, gaining vegetables and cheese early in the fight, but the operations team is holding steady at the cold meat platter. The senior staff has set up a strong defensive perimeter around the cold drinks tub and tense negotiations are taking place.
|Jeff:||OK folks, I'd just like to say thanks again, and enjoy the food.|
|Cindy:||Hey Jeff, I've been meaning to talk to you. Got a minute?|
|Cindy:||I've been reviewing the phone system logs. I do this regularly to see who is calling the help desk the most often and for how long, and I noticed something strange. . . .|
|Jeff:||(I hope it's not 1-900 numbers.)
|Cindy:||An external number that isn't shown dialed all our numbers sequentially|
|Jeff:||(Ah, the pizza guy is here.)
I'm sure it's just a glitch. I wouldn't worry about it.
|Cindy:||Well, OK. . . hey, you ordered pizza!|
|Pizza Guy:||Please don't hurt me!|
After a few hours, the happily fed IT staff have wandered back to their respective cubicles, content with their pizza and life in general. Not far away in a quiet wiring closet, a set of lights on an old terminal server start to blink and then, in a soft glow, stay on for several hours before blinking out.
To: [email protected]
From: [email protected]
Subject: Windows 2000
I have deployed a single Windows 2000 server to start the creation of our ADS tree, this ensures that one of you doesn't accidentally do it. Anyone deploying Windows 2000 server will please contact me first so we can integrate it into the existing system (of which their isn't much). I have a meeting with HR planned and following that their will be a technical meeting on Tuesday at 2pm.
|If you're going to deploy Windows 2000 and you know you will start planning now. Deploy a single server to act as the root of the ADS tree and to "hold" your domain name. ADS will come to depend on this, and changing it later is a nightmare.|
Sighing mightily, Jeff trundles out of the HR meeting with a dated org chart of the company. As he has quickly discovered, running an IT department involves much more then purely technical issues.
Jeff pushes the paper aside. On a fresh sheet, he begins to make a stripped-down organization chart of the company, and on another sheet, a list of what each organization is responsible for. Planning the deployment of a directory service is never easy going, and Jeff knows it will rapidly deepen into a quagmire if he doesn't first figure out the layout of the directory.
Meanwhile, in another building at Acme Corp., Cindy, the support lead, is puzzling over a list of telephone logs and on another screen viewing the scripts used to parse them. She crumples up a sheet of notepaper and kicks her chair back, wondering what to do next.
|If you think an attacker might be prowling inside your network, use something else than email to notify others, or else you might notify the attacker as well.|
As Cindy walks over to building 6 she gazes across to the proving grounds, a scarred and ugly stretch of land pierced by numerous small and large craters. Among other material, here rest the remains of Acme Corp. products that didn't meet the rigid safety specifications.
Knocking on Jeff's door, she considers the words she must choose.
Jeff hears a knock on his door and answers it. He lets Cindy into his office, wondering what's up.
"Have a seat." For some legroom, Cindy nudges a piece of debris away from the area in front of her chair.
"Jeff, I think we have a problem. . ." she starts, hoping to phrase it so he won't take it the wrong way. "You remember those phone logs I mentioned at the party?"
"Yes, what about them?" How nice it would be to go home and sleep.
"Well, it appears that someone dialed all our phone numbers, and that someone has also been using a dial-in port on one of our terminal servers."
"What terminal servers?" A pall of worry flashes across Jeff's face. "No one ever mentioned this to me!"
"We have some terminal servers for dial-in access, and it appears a Russian phone number has been using them, a lot."
|The technique that Jeff ignored until too late is known as wardialing. An attacker somehow gains access to a set of company phone numbers, and then uses a specialized tool to dial each of these numbers with a modem. Most of the time, the wardialing utility will reach a voice number. But occasionally, an attacker will find a bank of modems (often used for remote employee access), and attempt to exploit weaknesses in the host system.|
"What do you mean by a lot?" asks Jeff. The lack of internal security around here seems epidemic.
"Well, it's been in use for about six hours in the last two days. I think we have been broken into by a Russian hacker; I mentioned this to you several days ago at the pizza party."
"Hindsight is 20/20 what do you think we should do now?"
"Well Jeff, we could unplug the terminal server from the network to block access."
"No, I don't think that's such a good idea. He's probably compromised a number of internal machines and can get in over the Internet at this point. Arghhh!" Leaning back, he rubs his temples and wonders for a moment if taking this job was such a great idea after all.
Cindy tries again. "At a bare minimum, we should probably monitor what he is doing, and maybe we could slow down his access literally, crank the modems down to 9600 or something."
Jeff considers for a moment and nods in agreement. "Let's not make him suspicious. I'll see what I can do about monitoring his access, and then this weekend at 5 p.m. we'll shut down the terminal server and the Internet access, and start cleaning out the infected systems. While we're at it, I think we should conduct a physical sweep of all offices and look for people with modems attached to their computers."
Pondering this for a moment, Jeff swings his gaze down a haphazard pile of unopened software packages, industry gimmes, on the floor next to his desk.
|If Jeff's predecessor had exercised more foresight, Jeff wouldn't have to worry about hindsight. Be careful who knows the numbers of your modem banks. If possible, get numbers on a different exchange from those used by the rest of the company. Require better authentication than a simple username password system. Consider dial-back authentication. Set firm policies for remote access. Lastly, do as Cindy did, and pay attention to the phone logs.|
Cindy sighs. "This is going to make life miserable for the tech staff. I think we should offer performance bonuses to make up for this."
"I'll see what I can do. . . I agree, it won't be pretty if we make the troops do a forced march over the weekend. For now, I'll set up a box with some demo monitoring software I got from a vendor, and I'll order some new firewalls. I've already had the tech team sorting some of the wiring out, and we should be able to segment our network a bit. I've also decided we should reset all the user account passwords with the new password policy, users will have to choose a reasonably secure password."
"Wow, you're going to be a pretty unpopular guy come Monday, you know." Cindy grins to herself.
"Yeah I know, but it's got to be done. Hopefully this will let us get ahead of the curve."
Cindy gets up and stretches her neck. "Well, it can't get much worse, Jeff. At least we've got the software upgrade system in place and protected. You know, with the way our network servers have been put together we're probably better off just doing fresh installations on all the file, print and application servers, which are probably the ones with the most holes. Luckily, I was able to get the NT PDC and BDCs set up properly behind their own firewalls."
"Yeah, I was wondering who did that, Cindy. I think you may have saved our collective bacon. Where did you get the idea for that?"
"My niece is into computers, and she made that suggestion the last time there was a "take your daughter to work day." She's also the one that wrote the scripts to monitor call activity."
"Wow, how much did that cost us?"
"Nothing unless you count the sushi we had for lunch after she wrote them."
"Well, I guess we've done what we can for now. We'll call a staff meeting tomorrow in person, and avoid using the email system to discuss this. What a pain."
Cindy nods, exiting in a hurry. She grabs her coat and starts towards her car, taking a quick detour to look in on the terminal server. "I'll get you yet," she murmurs.
Has Cindy been taking her medication? Will Jeff manage to convince the tech team to work a full weekend? And why hasn't anyone let the cat out yet? These questions and more will be answered next week.
A brightly lit server room. Fans humming quietly, a glass wall at one end; on the other side we see a table with several people sitting around it. Scattered on the table are several pads of paper, pencils, pagers and a laptop. We see Jeff, eyes a healthy shade of bloodshot pink accented by dark bags underneath. Lifting a cup of cold coffee to his lips, he grimaces and takes a deep gulp, swallowing it hurriedly.
Cindy sits to his left, makeup long since removed, hair tied up with a loose piece of cat 5. She rubs her eyes and yawns softly. Andy looks at his notes with watery eyes and then glances around the table before speaking.
"OK folks, we found seven workstations with Back Orifice 2000 installed, and cleaned them off. We installed antivirus on every single server and workstation, so we shouldn't have to worry about that again. We've changed everyone's passwords to a random 8-digit string and set it so they have to change it. Cindy, you guys are ready for it?"
Cindy nods her head in assent. "I've got the entire helpdesk staff on for tomorrow to answer the phone. We've also left printed instructions taped to each monitor for how to call the helpdesk and get the new password. Basically, they phone up, identify themselves, we ask a personal question from info HR has on file, we then give them their password.
"We also have a list of all user accounts, and any accounts that people haven't phoned about by Friday we'll disable this should help us weed out old accounts. We'll also be able to create a mapping of usernames to people, so when people leave the company we can quickly remove their access."
|If you don't have some way in place for HR to get access revoked for employees that have just been fired or have quit, then you should start working on one.|
Jeff looks relieved. "Good work, I hadn't thought of that. OK, so we've got software up to date, systems cleaned up . . . but the modem pool is still exposed, for example. Anyone have any ideas about that?"
Andy glances around and decides to step forward. "Well, I did see a product a few months ago, I can't remember where, but it should solve our problems. It's called TeleWall. You plug it in before your PBX and it's a firewall for phone lines."
Jeff ponders this. "Hmm, can we block based on the phone number it's from, and what time it is?"
Andy grins. "You bet. You also can't get around it with *6l to block caller ID. It can also tell what kind of phone call it is, voice or data or fax, and we can do a lot of logging independent of the terminal server. It handles 24 lines, so that's perfect for our dial-in pool."
Yawning loudly, Jeff rubs his eyes. Then he sighs. "OK. If it's not too expensive I guess we should get one. We can then block that little weasel completely and get his phone number."
|You wouldn't put a server or workstation online without a firewall, yet we regularly expose phone lines and phone equipment to the world with absolutely no protection. You should consider a phone firewall, as there are many ways for internal and external adversaries to abuse your phone system by using the fax line to make long distance phone calls, for example.|
Cindy groans. "Can I please go home. . . . I have no feeling in the back of my head anymore. I think my brain feel asleep."
Jeff is silent for a moment. "No, I can feel mine and it hurts. We have one last area to cover and then we can leave. Andy, what do you think about implementing security policies on the Windows machines? I think we should prevent users from accessing the network control panel, which is how those seven workstations got infected.
"We should also look at only allowing certain programs to run on the machines that the data entry people use. We need to get a list of software that these people use, and we also need to figure out which parts of their workstations users do not need access to."
Andy nods his head. "Agreed. The main issue will be replicating the security policies between servers, but I think we can do it more reliably than using Microsoft's replicate service. We'll get some complaints from those power users, but I expect we'll save money on the helpdesk in the long run."
"Agreed, now can we please go home?" Standing now, Cindy looks around for her purse and starts to think about a hot bath.
"Definitely, get a good night's sleep. I'll be making a presentation to the board, and I think we're in good shape." Jeff stands up, knocking over a few empty coffee cups in the process before getting oriented and heading for the door.
Monday dawns bright and sunny. The birds twitter and chirp happily, blissfully unaware of the painful transition going on inside Acme Corp.'s main building. At the helpdesk we see phones ringing and a group of harried-looking techs.
"Hello, this is the helpdesk."
"You guys changed my password. I demand you change it back!"
"I'm sorry, but we can't do that. If you can give me your name and the username you use, we can tell you what your new password is."
"I don't want a new password! I want my old one."
"I'm sorry sir, but that's not possible. It's a new company policy it's to prevent unauthorized access to your account."
"Hrmph. Fine, my name is Joe Bloggs and my username is joebloggs."
"Thank you, and what are the last four digits of your social security number?"
"Uhmm . . . let me check . . . oh yes, 1-2-3-4."
"Thanks. Your new password is Qh3ghe5d. Once you log in, you will be prompted to change your password, so you can set it to whatever you like as long as it is eight letters or more and has upper-case letters and numbers."
"That's not very nice, you know, changing our passwords without warning."
"I'm sorry sir, but it came from the head of IT."
"Well, all right . . . thanks." Click.
In another, more peaceful part of the building, Andy hangs up the phone and stretches. Getting up, he walks over to Jeff's office and knocks on the door.
"OK, I ordered the TeleWall. It'll be here by tomorrow 10 a.m., so we can probably have it set up by noon. We should look at ordering some more so we can cover all our phone lines."
"Yeah, we should be able to afford that. Thank god for the budget increase."
The sun sets, the birds fall asleep, and before you could finish compiling a Linux kernel on a 386/20, the land starts to brighten again. Several hours later, in a dusty wiring closet, the sound of sneezing and a power screwdriver emanates. Andy wipes his forehead, happy to have the unit plugged in and wired up. Closing the door, he walks to his office and fires up the control program.
Hunting around his desk, he pulls out a manual and starts to read the instructions. After several hours of tinkering and fiddling, Andy decides to call it a day. He has configured the TeleWall to log all incoming phone numbers to the modem pool and block any voice and fax calls, as well as any outbound calls from the modem pool.
In a dark apartment somewhere in Moscow, Karl is frowning. He looks at his printed list of passwords, frowns, and types it in again.
Invalid entry, please try again
Will Karl fall into the freshly planted Venus flytrap? Does Jeff survive yet another board meeting? How securely is the third tape rack on the back wall of the server room secured?
TeleWall from SecureLogix
Last Updated on 03/10/2002
Copyright Kurt Seifried, [email protected] 2002