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Analysis of the Witty Worm
DavidMoore writes "The Cooperative Association for Internet Data Analysis (CAIDA) and the University of California, San Diego Computer Science Department have an
analysis of the recent Witty worm. Among other things, Witty was started in an organized manner with an order of magnitude more ground-zero hosts than any previous Internet worm."
It could also be that whoever wrote this worm found the vulnerability independently and had been writing code to exploit it, when he saw the security advisory go up he released it ASAP before people had a chance to patch their boxes. If the vulnerability hadn't been announced the worm may have been released later with a different payload.
The highest packet rate they saw was more than 23,000 per hour, sustained for at least one hour. The worm came out one day after eEye announced the vulnerability. It just went ahead and started erasing the hard drive, rather than just grep for passwords or credit card numbers. And this thing targeted and 0wned people who cared about the security of their computer!
If you've read nothing else, check out the conclusion:
I was thinking the other day about all the precautions you need to go through with a Windows box just to get a new install up-to-date; I was smug, and thinking that a Windows box without a firewall was like a person without a skin: no protection from infection, no way of stopping the most basic of attacks.
And now reading this I feel that smugness just draining in a really hideous way. I use Linux and FreeBSD...what of it? I realize there is still a big difference between Unix and Microsoft, between a local and a remote exploit, between an ordinary user account and root. But I'm no longer convinced those differences are enough: there's a thousand programs available on my machines, and all that stands between me and 0wnership is a programming error and someone who decides that, you know what, seven thousand hosts is worth it.
Nothing more to say at this point...I'm still staring uneasily at the blinking cable modem lights, wondering when it'll be my turn.
Carousel is a lie!
That's a very good suggestion, except that in this case, the firewall software was the vulnerable component. No BlackICE, no Witty worm.
I'm deeply troubled by this; we piss and moan about how the average windoze luser doesn't have a firewall or AV software, and then this pops up.
Much as I would like to, I can't blame this on Microsoft. It's just sloppy programming, the sort of practice that M$ has made prevalent. There, I blamed M$ after all. Still, changing the permission model of Windoze wouldn't have helped this; BlackICE is exactly the sort of software that needs access to the network protocol stacks; it's supposed to be one of the trusted portion of the system, as compared to all those VBScript viruses that run as admin/root, but shouldn't.
If I were designing a new CPU, I would think about including some hard-core stack protection. A no-execute bit in the MMU is a very good start, but still not bullet-proof. I'm thinking something (with OS assistance) to disallow all access beyond the link pointer for the current function call. Every CALL sets a new boundary, and every RET pops back to the last boundary. Try to write past the boundary, and you get a machine exception. Much finer granularity than 4K pages that most 32-bit MMU's provide.
-paul
Pistol caliber is like religion: everyone has their favourite, and theirs is the only right choice.
Under that conditions, if a similar flaw is found in i.e. iptables, ssh, bind, apache or postfix, it could have a similar impact, be the OS Linux, FreeBSD, MacOSX or whatever you consider "safe" and widely enough used.
Of course, if the same would happened to a really popular software out there (clients are more popular than servers, we know the effect of outlook worms, and even by default installed servers, like IIS, or maybe even the Win XP SP2's bundled firewall) the effect would be much worse, but no OS connected to internet is safe against this. Maybe releasing policies will change putting the "when its ready" release date over the "when the marketing people say" on the light or the widespread of this kind of things.
Ok, I'll bite. . .
/etc/passwd since these are Windows boxen, and don't HAVE an /etc/passwd file.
Yes, there are laws against writing malicious code. They apply if the authors happen to be in a country that respects the USAPatriot Act or whatever other laws may be applied. Your actual chances of catching these folks are slim to none.
Even with 100 "Ground Zero" hosts, you won't get anything from
Personally, I suspect the timing of the "destructive" release of this worm was based on the impending alerts about the 'sploit. I seriously doubt the creation of the worm happened after the public knowledge of the release. It's very likely that folks "in the know" were using the 'sploit for weeks to months before it was publicly acknowledged. The worm was "Spoil our fun, will you? Ha! Chew on this!"
The destructive payload was certainly viscious, but I would worry that there were exploited (with this particular 'sploit) boxen out there LONG before anyone knew there was a hole in RealSecure and BlackICE.
Never attribute to malice what can as easily be the result of incompetence...
I'm a long time UNIX/Linux hacker (I first programmed on UNIX on a VAX). I've written a lot of C/C++ code. But long ago I used Pascal and more recently I've been using Java more.
Both Pascal and Java do range checking. That is, they check the bounds of arrays (buffers) when they are accessed. This means that about half of the security exploits (including the one, targeted at BlackIce etc...) would not be exist if our software base was implemented in languages with bounds checking.
The original reason that bounds checking was not implemented in C was that the early compilers were very basic (little in the way of optimization) and bounds checking overhead slows execution. Bounds checking overhead can be reduced through optimization, but Ritchie's original C compiler only did simple optimization.
Another problem is that in C pointers and arrays are more or less interchangable. So bounds checking becomes difficult or impossible in all cases (C provides way too much pointer flexibility when it comes to enforcing bounds checking).
If we were to add up the cost of all of the buffer overflow security attacks it must run in the billions. So the "power" of the C programming model has extracted a pretty high price. This puts an interesting retrospective slant on Brian Kernighan's 1981 article Why Pascal is Not My Favorite Programming Language .
I have to confess that I would not go back to using Pascal. But native compiled Java, with Java's bounds checks, would be far safer than C++. And it would result in software that is more robust against security attacks.
Yes we can all learn to use fgets, strncpy and other safer library routines. But this only makes our code safer. It does not provide the complete protection against buffer overflow attacks. So perhaps it is time to reconsider the programming languages we are using. Perhaps unrestricted pointers and no bounds checking has become too costly.
A key point of modern tactical doctrine is to act faster than the opposition can react. Special operations types talk about the "period of vulnerability", which begins when the defender notices an attack and ends when the attacker achieves relative superiority. Most attacks fail during the period of vulnerability. So modern tactical doctrine says that it's worth huge amounts of effort and money to cut that time down. This is why special ops people rehearse and train to a level that seems unreasonable. It's not to make them good, athough it does. It's to make them fast, so they get through those first seconds and minutes at the beginning of an attack before the defenders can react.
That's exactly what we saw with this worm. The attack was launched in a way that rendered the usual strategies of anti-virus companies ineffective. Anti-virus companies, (and Microsoft), have known response and patching cycle times. The creators of this worm got inside that cycle time, by building both a fast-propagating worm and by starting it from multiple points.
Military doctrine gives us some insights on what to expect next. This worm invoved a campaign, a series of battles fought to achieve a goal. One attack acquired machines to be used as bases in a later attack. That's standard doctrine. Other relevant military concepts include mutual support, feints, and diversions. We are starting to see worms and viruses that support each other, so that if one is removed, another attack lets it back in. We may see feints and diversions, where a big noisy attack is launched to divert attention from something more subtle.
Another doctrinal concept is that of combined arms. So far, virus writers generally haven't utilized other hacking techniques, like dumpster diving, social engineering, or wiretapping. That may change.
We may well see an attack that wipes out most of the Internet-connected Windows machines in the world in a single day.
Is anyone else sensing the likelyhood that compromised MyDoom machines were the ground zero hosts?
An infinite number of monkeys will eventually come up with the complete works of
1) Internet Information Services's track record has improved dramatically in the last couple of years... the last security patch for it was in May of last year, and then the one before that was in 2002.
2) Why didn't you enable XP's firewall before connecting to the Internet? That's a pretty effective way of preventing your machine from getting infected while collecting the various updates.
Besides the fact that you're repeatedly trolling with the "Teaching Fellow" bit...
/etc/passwd FILE IN WINDOWS!. Assuming there magically was, it wouldn't have any useful information. Yes, they might find a username. Who cares? If you cracked a box to install a worm, would you use a username that might possibly be traced to you? Unless the owner is running some hardcore auditing software, it's highly unlikely that there would be a single clue as to the virus author.
I highly doubt that the hosts who own your 100 so-called "ground-zero" IP addresses would be very helpful in an investigation, besides perhaps a cursory inspection. First, why would they be different from any other infected host, besides the fact that their IPs were hard-coded in the virus? The owners haven't commited any crime, but if the FBI grabs those computers, they won't see their computers for months or years.
First, it's a Windows worm, and THERE ISN'T AN
Second, if the virus author was intelligent at all, these hosts would be chosen to be outside the US, preferably in Libya or China or Russia or somewhere else with a low chance of cooperation with US law enforcement. Why? It's harder to get them taken down.
I'm not denying that they should be brought to justice, but let's not send the FBI to start grabbing random computers every time there's a virus outbreak. How would you feel if the FBI demanded you give them your shiny new $3000 laptop for as long as they want?
Karma: Contrapositive
How many Linux, BSD, and Mac machines were infected?
Don't pretend that those haven't had remote root exploits before. (Well, not sure about Mac.) This incident seems to demonstrate that a destructive worm can be deployed in short order and rapidly spread even when the target population is in a tiny minority of internet hosts.
That prompted me to insert a bridging Linux firewall and want to learn to tighten it up even further. (Blocking 1-1024 now plus ports like 3128 & MSSQL; I want to block all unwanted incoming connections but am yet unsure about Freenet, Kazaa Lite, bittorrent and Quake3 inbound needs.)
(BTW, used LEAF uClib Bering for the bridging firewall. Axed the Shorewall and htb.init and put my own scripts in, though, due to issues with htb.init.)
It was an honest mistake. I was thinking of BlackIce and put the wrong firewalling program. Blame my lack of sleep for the error. The rest of the argument remains true, however. Whether a security hole was discovered in Zonealarm, Blackice, or in any other Windows program, unless the bug was caused by a problem with Windows itself, it is not in itself a Windows worm.
Another poster in the thread cited that worms affecting Outlook are Windows worms and Outlook is software that runs on Windows. The difference is that Outlook is bundled with IE, and is integrated into Windows and it is very difficult to seperate it. Surely I don't need to educate Slashbots on this. Since it is so tightly wrapped with Windows, and Microsoft claims it's an integral part of Windows (they told the DOJ that), then it's part of Windows. If the problem involves Windows, a component of Windows (such as a DLL shipped with it), or a program integrated into Windows or installed with Windows, then it's a Windows vulnerability. When BlackIce is installed with Windows by the Windows installer, then a BlackIce vulnerability would be considered a Windows vulnerability.
In terms of Linux, a particular distro would be said to have a vulnerability if it involves the actual operating system or a package that the distro releases along with the OS. If I go install some buggy unsupported software on my Linux box, and then there's a worm for it, should that worm be considered an exploit of that distro since I was running that distro and was infected by the worm? That's absurd.
I don't think you got the message.
Worms like this could run on your dedicated firewall box (like linksys or draytek).
They don't require Windows or an insecure OS at all, they just require sloppy programming in any program that handles network packets.
You are failing to consider the extent to which Windows internal architecture dictates the software running on the platform.
Most of the time Microsoft bashing is valid, but saying that this is Microsoft's fault in any way is about one step away from stupid.
If this was the fault of Windows, a buffer overflow such as this one could not happen under Linux/MacOS/FreeBSD/Netware etc etc etc. However, a quick search on SecurityFocus tells us that it did infact happen on all the platforms listed above.
So, please explain to me how Microsoft can be blamed for this in any way!
...and saying that they should not allow code-execution on the stack or make it more secure so you dont need a firewall are not valid arguments.
About a week ago, we had a vulnerability announced in OpenSSL. I imagine most of us patched pretty quickly. But the Witty worm appeared within twenty-four hours of the announcement of the vulnerability it attacked, and it infected 95% of vulnerable machines within 45 minutes.
Yes, it's funny that it was a Windows firewall that was attacked. Yes, it's especially funny that it was an expensive Windows firewall that was attacked. Laugh.
But also think.
This could just as easily have been us. From my root logs I patched my servers for the OpenSSL vulnerability on Sunday 21st, which was four days after it had been announced. If the Witty worm had attacked OpenSSL, it would have got me. I suspect it would get most of us.
Linux (or BSD, or whatever) is not immune to this sort of attack. On the contrary, we're just as vulnerable as anyone else. Those of us who administer public-facing servers have got to learn to be still more cautious, and still more proactive about fixing holes as they are announced.
I'm old enough to remember when discussions on Slashdot were well informed.
...anything that is called a "firewall":
1. Should NOT contain any attack analysis. The only attack that any security software not in the hands of security researcher has a legitimate reason to "analyze" is an attack that already succeeded, and the user is recovering from the destruction caused by it. Announcing "prevented" attacks or modifying the host's response to "suspicious" data is at least a useless toy, and at most a target for a real attack (though most often it's in the middle, a nuisance that reduces the reliability). Keep it simple, stupid!
2. Should be separated from the host that it protect by at least a virtual machine and (better) be on a separate device. Then the worst that can happen in the case of a firewall compromise is that the firewall will stop performing its functions. Running a "firewall" on the "firewalled" host is an equivalent of a person hiring himself as a bodyguard.
3. If running on the "protected" host, it should be passive, and merely prevent other software running on that host from receiving packets from the Internet even if that software listens on the ports that the author believes, should not be opened. Still, calling this a "firewall" stretches the definition way too far.
The original meaning of a firewall is a wall in the building that prevents fire from spreading when the building is already on fire, and firewall acts as a barrier for spreading it. It does not make a building non-flammable, and its design expects a building to contain flammable material, yet it prevents damage from spreading. A network firewall does something pretty close to this, it expect vulnerable hosts to be on either of its side, and merely reduces the probability of successful attack from "external" to "internal" network, yet being relatively simple, it is impossible or difficult to attack. Having a "firewall" full of "flammable" bells and whistles, and in the middle of a system that it assumes to be vulnerable is a very, very wrong kind of design.
Contrary to the popular belief, there indeed is no God.
From the analysis:
When users participating in the best security practice that can be reasonably expected get infected with a virulent and damaging worm, we need to reconsider the notion that end user behavior can solve or even effectively mitigate the malicious software problem and turn our attention toward both preventing software vulnerabilities in the first place and developing large-scale, robust and reliable infrastructure that can mitigate current security problems without relying on end user intervention.
Folks, we don't need any more infrastructure to prevent worms. We don't need any more infrastructure to control what you can and can't do on the Internet.
It's not the Internet that causes the problems, it's the in-secure machines that are vunerable.
You are being MICROattacked, from various angles, in a SOFT manner.
There is no reason on Earth that this worm couldn't have attacked Linux boxen. If this worm had been tailored to attack the the recent openssh vulnerability the day after it came out, many of us would have been owned immediately. How many of us have an open ssh port through our NAT devices and firewalls? The scary thing about this worm is that the authors have demonstrated an ability to attack new vulnerabilities in third-party software very quickly. In the case of the openssh vulnerability (a root exploit) that would have meant that very many of us Linux users would have been affected before we could do anything about it.
No matter how many of my rights are taken away, somehow I still don't feel safe. -Frigid Monkey