Detection rules › Sigma
Curl Web Request With Potential Custom User-Agent
Detects execution of "curl.exe" with a potential custom "User-Agent". Attackers can leverage this to download or exfiltrate data via "curl" to a domain that only accept specific "User-Agent" strings
Event coverage
| Provider | Event ID | Title |
|---|---|---|
| Sysmon | 1 | Process creation |
Stages and Predicates
Stage 1: selection_img
or:
Image|endswith: '\curl.exe'
OriginalFileName: curl.exe
Stage 2: 1 of selection_header_flag_1
CommandLine|re: '\s-H\s'
Stage 3: 1 of selection_header_flag_2
CommandLine|contains: --header
Stage 4: selection_user_agent
CommandLine|contains: 'User-Agent:'
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
CommandLine | match |
|
CommandLine | regex_match |
|
Image | ends_with |
|
OriginalFileName | eq |
|