Remote Services: VNC T1021.005

Tactic: Lateral Movement

Adversaries may use Valid Accounts to remotely control machines using Virtual Network Computing (VNC). VNC is a platform-independent desktop sharing system that uses the RFB (“remote framebuffer”) protocol to enable users to remotely control another computer’s display by relaying the screen, mouse, and keyboard inputs over the network.

Events covered

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

Authoring guide

Patterns shared across the 4 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 (9 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
CommandLine1contains 1-autoreconnect , -connect , -id:
DestinationPort1ge 1, le 15800, 5810
EventType1eq 1screensharing_attach, screensharing_detach
Protocol1eq 1tcp
aws::eventName1eq 1SendSSHPublicKey
data_stream.dataset1eq 1network_traffic.flow
esf.event_type1eq 1135, 136
event.category1in 1network, network_traffic
src_ip1in 110.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16

Top indicator values (17 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
CommandLinecontains
-autoreconnect
1
CommandLinecontains
-connect
1
CommandLinecontains
-id:
1
DestinationPortge
5800
12
DestinationPortle
5810
12
EventTypeeq
screensharing_attach
1
EventTypeeq
screensharing_detach
1
Protocoleq
tcp
118
aws::eventNameeq
SendSSHPublicKey
1
data_stream.dataseteq
network_traffic.flow
16
esf.event_typeeq
135
1
esf.event_typeeq
136
1
event.categoryin
network
115
event.categoryin
network_traffic
115
src_ipin
10.0.0.0/8
19
src_ipin
172.16.0.0/12
19
src_ipin
192.168.0.0/16
19

Exclusions (26 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
dest_ipin
10.0.0.0/8
1
dest_ipin
100.64.0.0/10
1
dest_ipin
127.0.0.0/8
1
dest_ipin
169.254.0.0/16
1
dest_ipin
172.16.0.0/12
1
dest_ipin
192.0.0.0/24
1
dest_ipin
192.0.0.0/29
1
dest_ipin
192.0.0.10/32
1
dest_ipin
192.0.0.170/32
1
dest_ipin
192.0.0.171/32
1
dest_ipin
192.0.0.8/32
1
dest_ipin
192.0.0.9/32
1
dest_ipin
192.0.2.0/24
1
dest_ipin
192.168.0.0/16
1
dest_ipin
192.175.48.0/24
1

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 2 rules

Elastic 1 rule

Panther 1 rule