Application Layer Protocol: DNS

Adversaries may communicate using the Domain Name System (DNS) application layer protocol to avoid detection/network filtering by blending in with existing traffic. Commands to the remote system, and often the results of those commands, will be embedded within the protocol traffic between the client and server.

The DNS protocol serves an administrative function in computer networking and thus may be very common in environments. DNS traffic may also be allowed even before network authentication is completed. DNS packets contain many fields and headers in which data can be concealed. Often known as DNS tunneling, adversaries may abuse DNS to communicate with systems under their control within a victim network while also mimicking normal, expected traffic.[1][2]

ID: T1071.004
Sub-technique of:  T1071
Platforms: Linux, Windows, macOS
Contributors: Chris Heald; Jan Petrov, Citi
Version: 1.1
Created: 15 March 2020
Last Modified: 17 June 2022

Procedure Examples

ID Name Description
S0504 Anchor

Variants of Anchor can use DNS tunneling to communicate with C2.[3][4]

G0026 APT18

APT18 uses DNS for C2 communications.[5]

G0087 APT39

APT39 has used remote access tools that leverage DNS in communications with C2.[6]

G0096 APT41

APT41 used DNS for C2 communications.[7][8]

S0360 BONDUPDATER

BONDUPDATER can use DNS and TXT records within its DNS tunneling protocol for command and control.[9]

G0114 Chimera

Chimera has used Cobalt Strike to encapsulate C2 in DNS traffic.[10]

G0080 Cobalt Group

Cobalt Group has used DNS tunneling for C2.[11][12][13]

S0154 Cobalt Strike

Cobalt Strike can use a custom command and control protocol that can be encapsulated in DNS. All protocols use their standard assigned ports.[14][15][16]

S0338 Cobian RAT

Cobian RAT uses DNS for C2.[17]

S1014 DanBot

DanBot can use use IPv4 A records and IPv6 AAAA DNS records in C2 communications.[18]

S0354 Denis

Denis has used DNS tunneling for C2 communications.[19][20][21]

S1021 DnsSystem

DnsSystem can direct queries to custom DNS servers and return C2 commands using TXT records.[22]

S0377 Ebury

Ebury has used DNS requests over UDP port 53 for C2.[23]

G0046 FIN7

FIN7 has performed C2 using DNS via A, OPT, and TXT records.[24]

S0666 Gelsemium

Gelsemium has the ability to use DNS in communication with C2.[25]

S0477 Goopy

Goopy has the ability to communicate with its C2 over DNS.[21]

S0690 Green Lambert

Green Lambert can use DNS for C2 communications.[26][27]

S0170 Helminth

Helminth can use DNS for C2.[28]

S1027 Heyoka Backdoor

Heyoka Backdoor can use DNS tunneling for C2 communications.[29]

S0070 HTTPBrowser

HTTPBrowser has used DNS for command and control.[30][31]

S0260 InvisiMole

InvisiMole has used a custom implementation of DNS tunneling to embed C2 communications in DNS requests and replies.[32]

G0004 Ke3chang

Ke3chang malware RoyalDNS has used DNS for C2.[33]

S1020 Kevin

Variants of Kevin can communicate over DNS through queries to the server for constructed domain names with embedded information.[34]

G0140 LazyScripter

LazyScripter has leveraged dynamic DNS providers for C2 communications.[35]

S0167 Matryoshka

Matryoshka uses DNS for C2.[36][37]

S1015 Milan

Milan has the ability to use DNS for C2 communications.[38][34][39]

S1047 Mori

Mori can use DNS tunneling to communicate with C2.[40][41]

S0699 Mythic

Mythic supports DNS-based C2 profiles.[42]

S0228 NanHaiShu

NanHaiShu uses DNS for the C2 communications.[43]

G0049 OilRig

OilRig has used DNS for C2 including the publicly available requestbin.net tunneling service.[44][45][46][47]

S0124 Pisloader

Pisloader uses DNS as its C2 protocol.[48]

S0013 PlugX

PlugX can be configured to use DNS for command and control.[30]

S0145 POWERSOURCE

POWERSOURCE uses DNS TXT records for C2.[49][50]

S0184 POWRUNER

POWRUNER can use DNS for C2 communications.[51][45]

S0269 QUADAGENT

QUADAGENT uses DNS for C2 communications.[52]

S0495 RDAT

RDAT has used DNS to communicate with the C2.[53]

S0125 Remsec

Remsec is capable of using DNS for C2.[54][55][56]

S0596 ShadowPad

ShadowPad has used DNS tunneling for C2 communications.[57]

S1019 Shark

Shark can use DNS in C2 communications.[38][39]

S0633 Sliver

Sliver can support C2 communications over DNS.[58][59][60]

S0615 SombRAT

SombRAT can communicate over DNS with the C2 server.[61][62]

S0157 SOUNDBITE

SOUNDBITE communicates via DNS for C2.[63]

S0559 SUNBURST

SUNBURST used DNS for C2 traffic designed to mimic normal SolarWinds API communications.[64]

S0146 TEXTMATE

TEXTMATE uses DNS TXT records for C2.[49]

G0081 Tropic Trooper

Tropic Trooper's backdoor has communicated to the C2 over the DNS protocol.[65]

S0514 WellMess

WellMess has the ability to use DNS tunneling for C2 communications.[66][67]

Mitigations

ID Mitigation Description
M1037 Filter Network Traffic

Consider filtering DNS requests to unknown, untrusted, or known bad domains and resources. Resolving DNS requests with on-premise/proxy servers may also disrupt adversary attempts to conceal data within DNS packets.

M1031 Network Intrusion Prevention

Network intrusion detection and prevention systems that use network signatures to identify traffic for specific adversary malware can be used to mitigate activity at the network level.

Detection

ID Data Source Data Component Detects
DS0029 Network Traffic Network Traffic Content

Monitor and analyze traffic patterns and packet inspection associated to protocol(s), leveraging SSL/TLS inspection for DNS over TLS (DoT) and DNS over HTTPS (DoH), that do not follow the expected protocol standards and traffic flows (e.g extraneous packets that do not belong to established flows, gratuitous or anomalous traffic patterns, anomalous syntax, or structure). Consider correlation with process monitoring and command line to detect anomalous processes execution and command line arguments associated to traffic patterns (e.g. monitor anomalies in use of files that do not normally initiate connections for respective protocol(s)).

Network Traffic Flow

Monitor for DNS traffic to/from known-bad or suspicious domains and analyze traffic flows that do not follow the expected protocol standards and traffic flows (e.g extraneous packets that do not belong to established flows, or gratuitous or anomalous traffic patterns). Consider correlation with process monitoring and command line to detect anomalous processes execution and command line arguments associated to traffic patterns (e.g. monitor anomalies in use of files that do not normally initiate connections for respective protocol(s)).

References

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  1. Jazi, H. (2021, February). LazyScripter: From Empire to double RAT. Retrieved November 24, 2021.
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