Browser Session Hijacking T1185

Tactic: Collection

Adversaries may take advantage of security vulnerabilities and inherent functionality in browser software to change content, modify user-behaviors, and intercept information as part of various browser session hijacking techniques.

Events covered

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

Authoring guide

Patterns shared across the 17 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 (26 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
CommandLine9contains 4, match 3, eq 2, in 1, wildcard 1(?i)\s+--remote-debugging-\S+, (?i)\s+-start-debugger-service, firefox.exe, --remote-debugging-, -start-debugger-server
process_name5eq 3, in 2chrome.exe, brave browser, brave.exe, firefox.exe, google chrome
sourcetype4eq 4aws:asl, aws:cloudtrail, azure:monitor:aad, o365:management:activity
EventID3eq 31, 4103, 4104, 4688
aws::eventName2eq 2DescribeEventAggregates
distinct_ip_count2gt 21
process.args2eq 1, starts_with 1, wildcard 1--load-extension=/, --remote-debugging-port=922?, --window-position=-*,-*
registry_path2contains 2\\google\\chrome\\extensioninstallallowlist, \\google\\update
Details1eq 10x00000000, 0x00000001
EventType1eq 1exec
Image1ends_with 1\firefox.exe
Operation1eq 1UserLoggedIn
ParentImage1is_not_null 1
Type1eq 1
UserAgentOriginal1is_not_null 1

Top indicator values (64 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
CommandLinematch
(?i)\s+--remote-debugging-\S+
33
CommandLinematch
(?i)\s+-start-debugger-service
22
CommandLinematch
(?i)firefox.+\s+-start-debugger-service
1
process_nameeq
chrome.exe
37
CommandLineeq
firefox.exe
22
aws::eventNameeq
DescribeEventAggregates
22
distinct_ip_countgt
1
24
CommandLinecontains
--remote-debugging-
1
CommandLinecontains
-start-debugger-server
1
CommandLinecontains
--disable-features
1
CommandLinecontains
--headless
18
CommandLinecontains
--load-extension
1
CommandLinecontains
--remote-debugging-
1
CommandLinecontains
--user-data-dir
12
CommandLinecontains
disableloadextensioncommandlineswitch
1
CommandLinein
*--do-not-de-elevate*
1
CommandLinein
*--mute-audio*
1
CommandLinein
*--no-de-elevate*
1
CommandLinewildcard
"C:\Program Files\Google\Chrome\Application\chrome.exe" --headless
1
CommandLinewildcard
"C:\Program Files\Google\Chrome\Application\chrome.exe" --headless...
1
CommandLinewildcard
"C:\Program Files\Google\Chrome\Application\chrome.exe" --headless --log-level=3
1
CommandLinewildcard
"C:\Program Files\Google\Chrome\Application\chrome.exe" --headless...
1
CommandLinewildcard
"C:\Program Files\Google\Chrome\Application\chrome.exe"...
1
CommandLinewildcard
C:\Program Files (x86)\Microsoft\Edge\Application\msedge.exe
1
CommandLinewildcard
C:\Program Files\Google\Chrome\Application\chrome.exe
1
Detailseq
0x00000000
143
Detailseq
0x00000001
163
EventIDeq
1
1237
EventIDeq
4103
1105
EventIDeq
4104
1268

Exclusions (21 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
ParentImagein
c:\\program files*
1
ParentImagein
c:\\windows\\system32\\*
1
ParentImagein
c:\\windows\\syswow64\\*
1
ParentImagewildcard
/applications/cypress.app/contents/macos/cypress
1
ParentImagewildcard
/applications/google chrome.app/contents/macos/google chrome
1
ParentImagewildcard
/opt/homebrew/caskroom/chromedriver/*/chromedriver
1
ParentImagewildcard
/users/*/library/caches/cypress/*/cypress.app/contents/macos/cypress
1
ParentImagewildcard
/usr/local/bin/chromedriver
1
ParentImagewildcard
c:\program files (x86)\*.exe
1
ParentImagewildcard
c:\program files\*.exe
1
ParentImagewildcard
c:\windows\explorer.exe
1
ParentImagewildcard
c:\windows\system32\rdpinit.exe
1
ParentImagewildcard
c:\windows\system32\runtimebroker.exe
1
ParentImagewildcard
c:\windows\system32\secocl64.exe
1
ParentImagewildcard
c:\windows\system32\sihost.exe
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 2 rules

Splunk 12 rules

Kusto 1 rule