Web Service: Dead Drop Resolver T1102.001

Tactic: Command & Control

Adversaries may use an existing, legitimate external Web service to host information that points to additional command and control (C2) infrastructure. Adversaries may post content, known as a dead drop resolver, on Web services with embedded (and often obfuscated/encoded) domains or IP addresses. Once infected, victims will reach out to and be redirected by these resolvers.

Events covered

2 catalog events are tagged with this technique by at least one rule.

ProviderEventTitle
SysmonEvent ID 3Network connection
ESFwriteFile Write (NOTIFY)

Authoring guide

Patterns shared across the 8 rules above: which fields they filter on, what specific values they look for, and what they exclude. The catalog normalizes field names across vendors so Sigma's Image, Elastic's process.name, and Splunk's process_name collapse into one row. Each rule contributes at most once per row.

Fields filtered most (12 distinct)

The fields most rules look at when detecting this technique. The How column shows the operators authors use (eq, wildcard, regex_match, match) and how often each appears. Sample values are concrete examples to start from, not an exhaustive list.

FieldRulesHowSample values
DestinationHostname4ends_with 2, is_null 1, starts_with 1, wildcard 1.t.me, 4shared.com, abuse.ch, azurewebsites.net, calendar.app.google
process_name4in 2, is_not_null 2, starts_with 2node, bash, cursor, osascript, python
host.os.type3eq 3
Image2contains 2, ends_with 2, eq 2, is_null 2, starts_with 2\appdata\local\discord\, \appdata\local\flock\, \appdata\local\google\chrome\application\chrome.exe
Initiated2eq 2true
c-uri2contains 2, match 1.ghostbin.co/paste/*/raw/, .hastebin.com/raw/, .paste.ee/r/, /pwndrop/
dns.question.name2is_not_null 2, wildcard 2*.2miners.com, *.4shared.com, *.antpool.com, *.blob.core.windows.net, *.blob.storage.azure.net
event.type2eq 2start
EventType1eq 1modification
file.extension1in 1js, py, sh
process.code_signature.exists1eq 1false
process.code_signature.trusted1eq 1false

Top indicator values (400 distinct)

Specific (field, operator, value) combinations the rules check for, ranked by how many rules under this technique use each one. The Corpus reach column counts how many rules across the entire catalog (any technique) check the same combination. High numbers point to widely-used indicators that are likely noisy on their own; combine them with another condition for useful signal. Blank means the combination is specific to rules under this technique. Click a value to expand the rules under this technique that use it.

FieldKindValueRules (here)Corpus reach
Imagecontains
\appdata\local\discord\
2
Imagecontains
\appdata\local\flock\
2
Imagecontains
\appdata\local\maxthon\
2
Imagecontains
\appdata\local\phoebe\
2
Imagecontains
\appdata\local\programs\opera\
2
Imagecontains
\appdata\local\vivaldi\
2
Imagecontains
c:\program files (x86)\safari\
2
Imagecontains
c:\program files\safari\
2
Imagecontains
c:\program files\windows defender advanced threat protection\
2
Imagecontains
c:\program files\windows defender\
2
Imagecontains
c:\programdata\microsoft\windows defender\platform\
2
Imageends_with
\appdata\local\google\chrome\application\chrome.exe
2
Imageends_with
\appdata\local\mozilla firefox\firefox.exe
2
Imageends_with
\avant.exe
2
Imageends_with
\brave.exe
211
Imageends_with
\discord.exe
22
Imageends_with
\falkon.exe
2
Imageends_with
\flock.exe
2
Imageends_with
\maxthon.exe
23
Imageends_with
\msedge.exe
214
Imageends_with
\msedgewebview2.exe
23
Imageends_with
\msmpeng.exe
22
Imageends_with
\mssense.exe
2
Imageends_with
\opera.exe
211
Imageends_with
\phoebe.exe
2
Imageends_with
\qtweb.exe
2
Imageends_with
\safari.exe
22
Imageends_with
\seamonkey.exe
23
Imageends_with
\slimbrowser.exe
2
Imageends_with
\vivaldi.exe
211

Exclusions (177 distinct)

Field/operator/value combinations excluded by rules under this technique (top-level not() clauses), sorted by how many rules exclude each. These are the false-positive paths the community has learned to filter out. A new rule that ignores the high-count entries here will likely fire on the same noisy paths. Click a value to expand the rules under this technique that exclude it.

FieldKindValueRules excluding
Imagecontains
\appdata\local\discord\
2
Imagecontains
\appdata\local\flock\
2
Imagecontains
\appdata\local\maxthon\
2
Imagecontains
\appdata\local\phoebe\
2
Imagecontains
\appdata\local\programs\opera\
2
Imagecontains
\appdata\local\vivaldi\
2
Imagecontains
c:\program files (x86)\safari\
2
Imagecontains
c:\program files\safari\
2
Imagecontains
c:\program files\windows defender advanced threat protection\
2
Imagecontains
c:\program files\windows defender\
2
Imagecontains
c:\programdata\microsoft\windows defender\platform\
2
Imageends_with
\appdata\local\google\chrome\application\chrome.exe
2
Imageends_with
\appdata\local\mozilla firefox\firefox.exe
2
Imageends_with
\avant.exe
2
Imageends_with
\brave.exe
2

Rules under this technique

Every rule in the catalog tagged with this technique, grouped by vendor. Click a rule title for its full predicates, exclusions, and indicators.

Platform (all)
Domain (all)

Sigma 4 rules

Elastic 4 rules