zeek/scripts/policy/frameworks/intel/seen/http-headers.zeek
Benjamin Bannier d5fd29edcd Prefer explicit construction to coercion in record initialization
While we support initializing records via coercion from an expression
list, e.g.,

    local x: X = [$x1=1, $x2=2];

this can sometimes obscure the code to readers, e.g., when assigning to
value declared and typed elsewhere. The language runtime has a similar
overhead since instead of just constructing a known type it needs to
check at runtime that the coercion from the expression list is valid;
this can be slower than just writing the readible code in the first
place, see #4559.

With this patch we use explicit construction, e.g.,

    local x = X($x1=1, $x2=2);
2025-07-11 16:28:37 -07:00

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@load base/frameworks/intel
@load ./where-locations
@load base/utils/addrs
event http_header(c: connection, is_orig: bool, name: string, value: string) &group="Intel::ADDR"
{
if ( ! is_orig )
return;
switch ( name )
{
case "HOST":
# Remove the occasional port value that shows up here.
local host = gsub(value, /:[[:digit:]]+$/, "");
if ( is_valid_ip(host) )
Intel::seen(Intel::Seen($host=to_addr(host),
$indicator_type=Intel::ADDR,
$conn=c,
$where=HTTP::IN_HOST_HEADER));
break;
case "X-FORWARDED-FOR":
if ( is_valid_ip(value) )
{
local addrs = extract_ip_addresses(value);
for ( i in addrs )
{
Intel::seen(Intel::Seen($host=to_addr(addrs[i]),
$indicator_type=Intel::ADDR,
$conn=c,
$where=HTTP::IN_X_FORWARDED_FOR_HEADER));
}
}
break;
}
}
event http_header(c: connection, is_orig: bool, name: string, value: string) &group="Intel::DOMAIN"
{
if ( ! is_orig || name != "HOST" )
return;
# Remove the occasional port value that shows up here.
local host = gsub(value, /:[[:digit:]]+$/, "");
if ( ! is_valid_ip(host) )
Intel::seen(Intel::Seen($indicator=host,
$indicator_type=Intel::DOMAIN,
$conn=c,
$where=HTTP::IN_HOST_HEADER));
}
event http_header(c: connection, is_orig: bool, name: string, value: string) &group="Intel::URL"
{
if ( ! is_orig || name != "REFERER" )
return;
Intel::seen(Intel::Seen($indicator=sub(value, /^.*:\/\//, ""),
$indicator_type=Intel::URL,
$conn=c,
$where=HTTP::IN_REFERRER_HEADER));
}
event http_header(c: connection, is_orig: bool, name: string, value: string) &group="Intel::SOFTWARE"
{
if ( ! is_orig || name != "USER-AGENT" )
return;
Intel::seen(Intel::Seen($indicator=value,
$indicator_type=Intel::SOFTWARE,
$conn=c,
$where=HTTP::IN_USER_AGENT_HEADER));
}