65 lines
1.2 KiB
Go
65 lines
1.2 KiB
Go
package dns
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import (
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"math/rand"
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"strings"
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"github.com/miekg/dns"
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)
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const letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
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// Generate a random string
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// https://stackoverflow.com/a/31832326
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func generate(length int) string {
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// Create byte array with length
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word := make([]byte, length)
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// Go through word
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for index := range word {
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// Set index to random letter
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word[index] = letterBytes[rand.Intn(len(letterBytes))]
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}
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return string(word)
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}
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// Query wildcard
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func Wildcard(client *dns.Client, resolvers []string, domain string) bool {
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for {
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// Generate subdomain
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subdomain := generate(10) + "." + domain
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// Create message
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message := new(dns.Msg)
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// Set question
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message.SetQuestion(dns.Fqdn(subdomain), dns.TypeA)
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// Choose random resolver
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resolver := resolvers[rand.Intn(len(resolvers))]
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// Query response
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response, _, err := client.Exchange(message, resolver)
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if err != nil {
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// Ratelimited
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if strings.ContainsAny(err.Error(), "i/o timeout") {
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continue
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}
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return false
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}
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// Store status
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var status bool
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// Go through answers
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for _, answer := range response.Answer {
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// Map record
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_, status = answer.(*dns.A)
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}
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return status
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}
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}
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