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35 lines
1.1 KiB
35 lines
1.1 KiB
4 months ago
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This is a harness to help with fuzzing KEX.
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To use it, you first set it to count packets in each direction:
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./kexfuzz -K diffie-hellman-group1-sha1 -k host_ed25519_key -c
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S2C: 29
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C2S: 31
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Then get it to record a particular packet (in this case the 4th
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packet from client->server):
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./kexfuzz -K diffie-hellman-group1-sha1 -k host_ed25519_key \
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-d -D C2S -i 3 -f packet_3
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Fuzz the packet somehow:
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dd if=/dev/urandom of=packet_3 bs=32 count=1 # Just for example
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Then re-run the key exchange substituting the modified packet in
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its original sequence:
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./kexfuzz -K diffie-hellman-group1-sha1 -k host_ed25519_key \
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-r -D C2S -i 3 -f packet_3
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A comprehensive KEX fuzz run would fuzz every packet in both
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directions for each key exchange type and every hostkey type.
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This will take some time.
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Limitations: kexfuzz can't change the ordering of packets at
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present. It is limited to replacing individual packets with
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fuzzed variants with the same type. It really should allow
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insertion, deletion on replacement of packets too.
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$OpenBSD: README,v 1.3 2017/10/20 02:13:41 djm Exp $
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