ATT&CK coverage › Technique

Network Share Discovery T1135

Adversaries may look for folders and drives shared on remote systems as a means of identifying sources of information to gather as a precursor for Collection and to identify potential systems of interest for Lateral Movement. Networks often contain shared network drives and folders that enable users to access file directories on various systems across a network.

Events covered

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

ProviderEvent IDTitle
Sysmon1Process creation
Security-Auditing4672Special privileges assigned to new logon.
Security-Auditing4688A new process has been created.
Security-Auditing4769A Kerberos service ticket was requested.
Security-Auditing5140A network share object was accessed.
Security-Auditing5143A network share object was modified.
Security-Auditing5145A network share object was checked to see whether client can be granted desired access.
PowerShell4104Creating Scriptblock text (MessageNumber of MessageTotal).

Authoring guide

Patterns shared across the 11 rules above: which fields they filter on, what specific values they look for, and what they exclude. Field names are normalized 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 (13 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
EventID6eq 65140, 5143, 5145, 4104, 4769
Image4ends_with 2, match 2\explorer.exe, \SharpView.exe, \advanced_ip_scanner, \advanced_port_scanner
CommandLine4match 4/lng, /portable, shell:mycomputerfolder, Get-DomainForeign, Get-DFSshare
OriginalFileName3match 2, eq 1SharpView.exe, advanced_ip_scanner, advanced_port_scanner
unique_targets3gt 330
Description2match 2Advanced IP Scanner, Advanced Port Scanner
ShareName2in 1, eq 1"\\\\*\\ADMIN$", "\\\\*\\C$", "*\\\\*\\IPC$", "\\\\*\\IPC$"
DACLS1starts_with 1A;
ParentImage1ends_with 1\powershell.exe, \cmd.exe, \pwsh.exe
AccessMask1eq 10x1
ScriptBlockText1eq 1Invoke-ShareFinder*
ServiceName1eq 1"*$"
user1ne 1"*$"

Top indicator values (115 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.

FieldKindValueRules (here)Corpus reach
unique_targetsgt3035
CommandLinematch/portable22
CommandLinematch/lng22
EventIDeq514022
DACLSstarts_withA;1
EventIDeq51431
ParentImageends_with\cmd.exe113
ParentImageends_with\powershell.exe116
ParentImageends_with\pwsh.exe116
Imageends_with\explorer.exe112
CommandLinematchshell:mycomputerfolder1
CommandLinematchGet-DomainFileServer1
CommandLinematchGet-LastLoggedOn1
CommandLinematchSet-DomainObject1
CommandLinematchGet-NetSite1
CommandLinematchGet-DomainDFSShare1
CommandLinematchInvoke-ACLScanner12
CommandLinematchGet-NetDomain1
CommandLinematchGet-NetShare1
Imageends_with\SharpView.exe12

Common exclusions (7 distinct)

Field/operator/value combinations that rules under this technique routinely exclude (top-level not() clauses). 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.

FieldKindValueRules excluding
userin"LOCAL SERVICE"1
userin"DWM-3"1
userin"SYSTEM"1
userin"*$"1
userin"DWM-1"1
userin"NETWORK SERVICE"1
userin"DWM-2"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.

Sigma 4 rules

Splunk 5 rules

Kusto Query Language 2 rules