Feature/rules improvements #338
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Signed-off-by: Amit Schendel <amitschendel@gmail.com>
Signed-off-by: Amit Schendel <amitschendel@gmail.com>
Signed-off-by: Amit Schendel <amitschendel@gmail.com>
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Summary:
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Signed-off-by: Amit Schendel <amitschendel@gmail.com>
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Summary:
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slashben
approved these changes
Aug 14, 2024
matthyx
approved these changes
Aug 14, 2024
slashben
approved these changes
Aug 14, 2024
Comment on lines
+74
to
+105
| // Check for SSH signature using memcmp | ||
| if (__builtin_memcmp(payload, SSH_SIGNATURE, SSH_SIG_LEN) == 0) { | ||
| struct event *event; | ||
| __u32 zero = 0; | ||
| event = bpf_map_lookup_elem(&empty_event, &zero); | ||
| if (!event) { | ||
| return 0; | ||
| } | ||
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| // Enrich event with process metadata | ||
| struct sockets_value *skb_val = gadget_socket_lookup(skb); | ||
| if (skb_val != NULL) { | ||
| event->netns = skb->cb[0]; // cb[0] initialized by dispatcher.bpf.c | ||
| event->mntns_id = skb_val->mntns; | ||
| event->pid = skb_val->pid_tgid >> 32; | ||
| event->uid = (__u32)(skb_val->uid_gid); | ||
| event->gid = (__u32)(skb_val->uid_gid >> 32); | ||
| __builtin_memcpy(&event->comm, skb_val->task, sizeof(event->comm)); | ||
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| event->src_ip = iph.saddr; | ||
| event->dst_ip = iph.daddr; | ||
| event->src_port = bpf_ntohs(tcph.source); | ||
| event->dst_port = bpf_ntohs(tcph.dest); | ||
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| event->timestamp = bpf_ktime_get_boot_ns(); | ||
| } | ||
| __u64 skb_len = skb->len; | ||
| bpf_perf_event_output(skb, &events, skb_len << 32 | BPF_F_CURRENT_CPU, event, sizeof(struct event)); | ||
| } | ||
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| return 0; | ||
| } |
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@amitschendel , if I understand correctly, this will fire an event for every SSH frame. I am not sure we need event per packet, maybe per connection.
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I take the above back. The SSH_ header is only there in the handshake messages (one that client sends to server, the second when the server sends to the client)
Still, will we get two alerts here?
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Correct, this is why I am filtering out the response in the rule.
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