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Diffstat (limited to '')
| -rw-r--r-- | rules/headers_checks.lua | 1174 |
1 files changed, 1174 insertions, 0 deletions
diff --git a/rules/headers_checks.lua b/rules/headers_checks.lua new file mode 100644 index 0000000..92ebb0c --- /dev/null +++ b/rules/headers_checks.lua @@ -0,0 +1,1174 @@ +--[[ +Copyright (c) 2022, Vsevolod Stakhov <vsevolod@rspamd.com> + +Licensed under the Apache License, Version 2.0 (the "License"); +you may not use this file except in compliance with the License. +You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, software +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. +]]-- + +local util = require "rspamd_util" +local ipairs = ipairs +local pairs = pairs +local table = table +local tostring = tostring +local tonumber = tonumber +local fun = require "fun" +local E = {} + +local rcvd_cb_id = rspamd_config:register_symbol { + name = 'CHECK_RECEIVED', + type = 'callback', + score = 0.0, + group = 'headers', + callback = function(task) + local cnts = { + [1] = 'ONE', + [2] = 'TWO', + [3] = 'THREE', + [5] = 'FIVE', + [7] = 'SEVEN', + [12] = 'TWELVE' + } + local def = 'ZERO' + local received = task:get_received_headers() + local nreceived = fun.reduce(function(acc, rcvd) + return acc + 1 + end, 0, fun.filter(function(h) + return not h['flags']['artificial'] + end, received)) + + for k, v in pairs(cnts) do + if nreceived >= tonumber(k) then + def = v + end + end + + task:insert_result('RCVD_COUNT_' .. def, 1.0, tostring(nreceived)) + end +} + +rspamd_config:register_symbol { + name = 'RCVD_COUNT_ZERO', + score = 0.0, + parent = rcvd_cb_id, + type = 'virtual', + description = 'Message has no Received headers', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'RCVD_COUNT_ONE', + score = 0.0, + parent = rcvd_cb_id, + type = 'virtual', + description = 'Message has one Received header', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'RCVD_COUNT_TWO', + score = 0.0, + parent = rcvd_cb_id, + type = 'virtual', + description = 'Message has two Received headers', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'RCVD_COUNT_THREE', + score = 0.0, + parent = rcvd_cb_id, + type = 'virtual', + description = 'Message has 3-5 Received headers', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'RCVD_COUNT_FIVE', + score = 0.0, + parent = rcvd_cb_id, + type = 'virtual', + description = 'Message has 5-7 Received headers', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'RCVD_COUNT_SEVEN', + score = 0.0, + parent = rcvd_cb_id, + type = 'virtual', + description = 'Message has 7-11 Received headers', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'RCVD_COUNT_TWELVE', + score = 0.0, + parent = rcvd_cb_id, + type = 'virtual', + description = 'Message has 12 or more Received headers', + group = 'headers', +} + +local prio_cb_id = rspamd_config:register_symbol { + name = 'HAS_X_PRIO', + type = 'callback', + description = 'X-Priority check callback rule', + score = 0.0, + group = 'headers', + callback = function(task) + local cnts = { + [1] = 'ONE', + [2] = 'TWO', + [3] = 'THREE', + [5] = 'FIVE', + } + local def = 'ZERO' + local xprio = task:get_header('X-Priority'); + if not xprio then + return false + end + local _, _, x = xprio:find('^%s?(%d+)'); + if (x) then + x = tonumber(x) + for k, v in pairs(cnts) do + if x >= tonumber(k) then + def = v + end + end + task:insert_result('HAS_X_PRIO_' .. def, 1.0, tostring(x)) + end + end +} +rspamd_config:register_symbol { + name = 'HAS_X_PRIO_ZERO', + score = 0.0, + parent = prio_cb_id, + type = 'virtual', + description = 'Message has X-Priority header set to 0', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'HAS_X_PRIO_ONE', + score = 0.0, + parent = prio_cb_id, + type = 'virtual', + description = 'Message has X-Priority header set to 1', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'HAS_X_PRIO_TWO', + score = 0.0, + parent = prio_cb_id, + type = 'virtual', + description = 'Message has X-Priority header set to 2', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'HAS_X_PRIO_THREE', + score = 0.0, + parent = prio_cb_id, + type = 'virtual', + description = 'Message has X-Priority header set to 3 or 4', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'HAS_X_PRIO_FIVE', + score = 0.0, + parent = prio_cb_id, + type = 'virtual', + description = 'Message has X-Priority header set to 5 or higher', + group = 'headers', +} + +local function get_raw_header(task, name) + return ((task:get_header_full(name) or {})[1] or {})['value'] +end + +local check_replyto_id = rspamd_config:register_symbol({ + type = 'callback', + name = 'CHECK_REPLYTO', + score = 0.0, + group = 'headers', + callback = function(task) + local replyto = get_raw_header(task, 'Reply-To') + if not replyto then + return false + end + local rt = util.parse_mail_address(replyto, task:get_mempool()) + if not (rt and rt[1] and (string.len(rt[1].addr) > 0)) then + task:insert_result('REPLYTO_UNPARSEABLE', 1.0) + return false + else + local rta = rt[1].addr + task:insert_result('HAS_REPLYTO', 1.0, rta) + -- Check if Reply-To address starts with title seen in display name + local sym = task:get_symbol('FROM_NAME_HAS_TITLE') + local title = (((sym or E)[1] or E).options or E)[1] + if title then + rta = rta:lower() + if rta:find('^' .. title) then + task:insert_result('REPLYTO_EMAIL_HAS_TITLE', 1.0) + end + end + end + + -- See if Reply-To matches From in some way + local from = task:get_from { 'mime', 'orig' } + local from_h = get_raw_header(task, 'From') + if not (from and from[1]) then + return false + end + if (from_h and from_h == replyto) then + -- From and Reply-To are identical + task:insert_result('REPLYTO_EQ_FROM', 1.0) + else + if (from and from[1]) then + -- See if From and Reply-To addresses match + if (util.strequal_caseless(from[1].addr, rt[1].addr)) then + task:insert_result('REPLYTO_ADDR_EQ_FROM', 1.0) + elseif from[1].domain and rt[1].domain then + if (util.strequal_caseless(from[1].domain, rt[1].domain)) then + task:insert_result('REPLYTO_DOM_EQ_FROM_DOM', 1.0) + else + -- See if Reply-To matches the To address + local to = task:get_recipients(2) + if (to and to[1] and to[1].addr:lower() == rt[1].addr:lower()) then + -- Ignore this for mailing-lists and automatic submissions + if (not (task:get_header('List-Unsubscribe') or + task:get_header('X-To-Get-Off-This-List') or + task:get_header('X-List') or + task:get_header('Auto-Submitted'))) + then + task:insert_result('REPLYTO_EQ_TO_ADDR', 1.0) + end + else + task:insert_result('REPLYTO_DOM_NEQ_FROM_DOM', 1.0) + end + end + end + -- See if the Display Names match + if (from[1].name and rt[1].name and + util.strequal_caseless(from[1].name, rt[1].name)) then + task:insert_result('REPLYTO_DN_EQ_FROM_DN', 1.0) + end + end + end + end +}) + +rspamd_config:register_symbol { + name = 'REPLYTO_UNPARSEABLE', + score = 1.0, + parent = check_replyto_id, + type = 'virtual', + description = 'Reply-To header could not be parsed', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'HAS_REPLYTO', + score = 0.0, + parent = check_replyto_id, + type = 'virtual', + description = 'Has Reply-To header', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'REPLYTO_EQ_FROM', + score = 0.0, + parent = check_replyto_id, + type = 'virtual', + description = 'Reply-To header is identical to From header', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'REPLYTO_ADDR_EQ_FROM', + score = 0.0, + parent = check_replyto_id, + type = 'virtual', + description = 'Reply-To header is identical to SMTP From', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'REPLYTO_DOM_EQ_FROM_DOM', + score = 0.0, + parent = check_replyto_id, + type = 'virtual', + description = 'Reply-To domain matches the From domain', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'REPLYTO_DOM_NEQ_FROM_DOM', + score = 0.0, + parent = check_replyto_id, + type = 'virtual', + description = 'Reply-To domain does not match the From domain', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'REPLYTO_DN_EQ_FROM_DN', + score = 0.0, + parent = check_replyto_id, + type = 'virtual', + description = 'Reply-To display name matches From', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'REPLYTO_EMAIL_HAS_TITLE', + score = 2.0, + parent = check_replyto_id, + type = 'virtual', + description = 'Reply-To header has title', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'REPLYTO_EQ_TO_ADDR', + score = 5.0, + parent = check_replyto_id, + type = 'virtual', + description = 'Reply-To is the same as the To address', + group = 'headers', +} + +rspamd_config:register_dependency('CHECK_REPLYTO', 'CHECK_FROM') + +local check_mime_id = rspamd_config:register_symbol { + name = 'CHECK_MIME', + type = 'callback', + group = 'headers', + score = 0.0, + callback = function(task) + -- Check if there is a MIME-Version header + local missing_mime = false + if not task:has_header('MIME-Version') then + missing_mime = true + end + + -- Check presence of MIME specific headers + local has_ct_header = task:has_header('Content-Type') + local has_cte_header = task:has_header('Content-Transfer-Encoding') + + -- Add the symbol if we have MIME headers, but no MIME-Version + -- (do not add the symbol for RFC822 messages) + if (has_ct_header or has_cte_header) and missing_mime then + task:insert_result('MISSING_MIME_VERSION', 1.0) + end + + local found_ma = false + local found_plain = false + local found_html = false + + for _, p in ipairs(task:get_parts()) do + local mtype, subtype = p:get_type() + local ctype = mtype:lower() .. '/' .. subtype:lower() + if (ctype == 'multipart/alternative') then + found_ma = true + end + if (ctype == 'text/plain') then + found_plain = true + end + if (ctype == 'text/html') then + found_html = true + end + end + + if (found_ma) then + if (not found_plain) then + task:insert_result('MIME_MA_MISSING_TEXT', 1.0) + end + if (not found_html) then + task:insert_result('MIME_MA_MISSING_HTML', 1.0) + end + end + end +} + +rspamd_config:register_symbol { + name = 'MISSING_MIME_VERSION', + score = 2.0, + parent = check_mime_id, + type = 'virtual', + description = 'MIME-Version header is missing in MIME message', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'MIME_MA_MISSING_TEXT', + score = 2.0, + parent = check_mime_id, + type = 'virtual', + description = 'MIME multipart/alternative missing text/plain part', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'MIME_MA_MISSING_HTML', + score = 1.0, + parent = check_mime_id, + type = 'virtual', + description = 'MIME multipart/alternative missing text/html part', + group = 'headers', +} + +-- Used to be called IS_LIST +rspamd_config.PREVIOUSLY_DELIVERED = { + callback = function(task) + if not task:has_recipients(2) then + return false + end + local to = task:get_recipients(2) + local rcvds = task:get_header_full('Received') + if not rcvds then + return false + end + for _, rcvd in ipairs(rcvds) do + local _, _, addr = rcvd['decoded']:lower():find("%sfor%s<(.-)>") + if addr then + for _, toa in ipairs(to) do + if toa and toa.addr:lower() == addr then + return true, addr + end + end + return false + end + end + end, + description = 'Message either to a list or was forwarded', + group = 'headers', + score = 0.0 +} +rspamd_config.BROKEN_HEADERS = { + callback = function(task) + return task:has_flag('broken_headers') + end, + score = 10.0, + group = 'headers', + description = 'Headers structure is likely broken' +} + +rspamd_config.BROKEN_CONTENT_TYPE = { + callback = function(task) + return fun.any(function(p) + return p:is_broken() + end, + task:get_parts()) + end, + score = 1.5, + group = 'headers', + description = 'Message has part with broken content type' +} + +rspamd_config.HEADER_RCONFIRM_MISMATCH = { + callback = function(task) + local header_from = nil + local cread = task:get_header('X-Confirm-Reading-To') + + if task:has_from('mime') then + header_from = task:get_from('mime')[1] + end + + local header_cread = nil + if cread then + local headers_cread = util.parse_mail_address(cread, task:get_mempool()) + if headers_cread then + header_cread = headers_cread[1] + end + end + + if header_from and header_cread then + if not string.find(header_from['addr'], header_cread['addr']) then + return true + end + end + + return false + end, + + score = 2.0, + group = 'headers', + description = 'Read confirmation address is different to from address' +} + +rspamd_config.HEADER_FORGED_MDN = { + callback = function(task) + local mdn = task:get_header('Disposition-Notification-To') + if not mdn then + return false + end + local header_rp = nil + + if task:has_from('smtp') then + header_rp = task:get_from('smtp')[1] + end + + -- Parse mail addr + local headers_mdn = util.parse_mail_address(mdn, task:get_mempool()) + + if headers_mdn and not header_rp then + return true + end + if header_rp and not headers_mdn then + return false + end + if not headers_mdn and not header_rp then + return false + end + + local found_match = false + for _, h in ipairs(headers_mdn) do + if util.strequal_caseless(h['addr'], header_rp['addr']) then + found_match = true + break + end + end + + return (not found_match) + end, + + score = 2.0, + group = 'headers', + description = 'Read confirmation address is different to return path' +} + +local headers_unique = { + ['Content-Type'] = 1.0, + ['Content-Transfer-Encoding'] = 1.0, + -- https://tools.ietf.org/html/rfc5322#section-3.6 + ['Date'] = 0.1, + ['From'] = 1.0, + ['Sender'] = 1.0, + ['Reply-To'] = 1.0, + ['To'] = 0.2, + ['Cc'] = 0.1, + ['Bcc'] = 0.1, + ['Message-ID'] = 0.7, + ['In-Reply-To'] = 0.7, + ['References'] = 0.3, + ['Subject'] = 0.7 +} + +local multiple_unique_headers_id = rspamd_config:register_symbol { + name = 'MULTIPLE_UNIQUE_HEADERS', + callback = function(task) + local res = 0 + local max_mult = 0.0 + local res_tbl = {} + local found = 0 + + for hdr, mult in pairs(headers_unique) do + local hc = task:get_header_count(hdr) + found = found + hc + + if hc > 1 then + res = res + 1 + table.insert(res_tbl, hdr) + if max_mult < mult then + max_mult = mult + end + end + end + + if res > 0 then + task:insert_result('MULTIPLE_UNIQUE_HEADERS', max_mult, table.concat(res_tbl, ',')) + elseif found == 0 then + task:insert_result('MISSING_ESSENTIAL_HEADERS', 1.0) + end + end, + + score = 7.0, + group = 'headers', + one_shot = true, + description = 'Repeated unique headers' +} + +rspamd_config:register_symbol { + name = 'MISSING_ESSENTIAL_HEADERS', + score = 7.0, + group = 'blankspam', + parent = multiple_unique_headers_id, + type = 'virtual', + description = 'Common headers were entirely absent', +} + +rspamd_config.MISSING_FROM = { + callback = function(task) + local from = task:get_header('From') + if from == nil or from == '' then + return true + end + return false + end, + score = 2.0, + group = 'headers', + description = 'Missing From header' +} + +rspamd_config.MULTIPLE_FROM = { + callback = function(task) + local from = task:get_from('mime') + if from and from[2] then + return true, 1.0, fun.totable(fun.map(function(a) + return a.raw + end, from)) + end + return false + end, + score = 8.0, + group = 'headers', + description = 'Multiple addresses in From header' +} + +rspamd_config.MV_CASE = { + callback = function(task) + return task:has_header('Mime-Version', true) + end, + description = 'Mime-Version .vs. MIME-Version', + score = 0.5, + group = 'headers' +} + +local check_from_id = rspamd_config:register_symbol { + name = 'CHECK_FROM', + type = 'callback', + score = 0.0, + group = 'headers', + callback = function(task) + local envfrom = task:get_from(1) + local from = task:get_from(2) + if (envfrom and envfrom[1] and not envfrom[1]["flags"]["valid"]) then + task:insert_result('ENVFROM_INVALID', 1.0) + end + if (from and from[1]) then + if not (from[1]["flags"]["valid"]) then + task:insert_result('FROM_INVALID', 1.0) + end + if (from[1].name == nil or from[1].name == '') then + task:insert_result('FROM_NO_DN', 1.0) + elseif (from[1].name and + util.strequal_caseless(from[1].name, from[1].addr)) then + task:insert_result('FROM_DN_EQ_ADDR', 1.0) + elseif (from[1].name and from[1].name ~= '') then + task:insert_result('FROM_HAS_DN', 1.0) + -- Look for Mr/Mrs/Dr titles + local n = from[1].name:lower() + local match, match_end + match, match_end = n:find('^mrs?[%.%s]') + if match then + task:insert_result('FROM_NAME_HAS_TITLE', 1.0, n:sub(match, match_end - 1)) + end + match, match_end = n:find('^dr[%.%s]') + if match then + task:insert_result('FROM_NAME_HAS_TITLE', 1.0, n:sub(match, match_end - 1)) + end + -- Check for excess spaces + if n:find('%s%s') then + task:insert_result('FROM_NAME_EXCESS_SPACE', 1.0) + end + end + + if envfrom then + if util.strequal_caseless(envfrom[1].addr, from[1].addr) then + task:insert_result('FROM_EQ_ENVFROM', 1.0) + elseif envfrom[1].addr ~= '' then + task:insert_result('FROM_NEQ_ENVFROM', 1.0, from[1].addr, envfrom[1].addr) + end + end + end + + local to = task:get_recipients(2) + if not (to and to[1] and #to == 1 and from and from[1]) then + return false + end + -- Check if FROM == TO + if (util.strequal_caseless(to[1].addr, from[1].addr)) then + task:insert_result('TO_EQ_FROM', 1.0) + elseif (to[1].domain and from[1].domain and + util.strequal_caseless(to[1].domain, from[1].domain)) + then + task:insert_result('TO_DOM_EQ_FROM_DOM', 1.0) + end + end +} + +rspamd_config:register_symbol { + name = 'ENVFROM_INVALID', + score = 2.0, + group = 'headers', + parent = check_from_id, + type = 'virtual', + description = 'Envelope from does not have a valid format', +} +rspamd_config:register_symbol { + name = 'FROM_INVALID', + score = 2.0, + group = 'headers', + parent = check_from_id, + type = 'virtual', + description = 'From header does not have a valid format', +} +rspamd_config:register_symbol { + name = 'FROM_NO_DN', + score = 0.0, + group = 'headers', + parent = check_from_id, + type = 'virtual', + description = 'From header does not have a display name', +} +rspamd_config:register_symbol { + name = 'FROM_DN_EQ_ADDR', + score = 1.0, + group = 'headers', + parent = check_from_id, + type = 'virtual', + description = 'From header display name is the same as the address', +} +rspamd_config:register_symbol { + name = 'FROM_HAS_DN', + score = 0.0, + group = 'headers', + parent = check_from_id, + type = 'virtual', + description = 'From header has a display name', +} +rspamd_config:register_symbol { + name = 'FROM_NAME_EXCESS_SPACE', + score = 1.0, + group = 'headers', + parent = check_from_id, + type = 'virtual', + description = 'From header display name contains excess whitespace', +} +rspamd_config:register_symbol { + name = 'FROM_NAME_HAS_TITLE', + score = 1.0, + group = 'headers', + parent = check_from_id, + type = 'virtual', + description = 'From header display name has a title (Mr/Mrs/Dr)', +} +rspamd_config:register_symbol { + name = 'FROM_EQ_ENVFROM', + score = 0.0, + group = 'headers', + parent = check_from_id, + type = 'virtual', + description = 'From address is the same as the envelope', +} +rspamd_config:register_symbol { + name = 'FROM_NEQ_ENVFROM', + score = 0.0, + group = 'headers', + parent = check_from_id, + type = 'virtual', + description = 'From address is different to the envelope', +} +rspamd_config:register_symbol { + name = 'TO_EQ_FROM', + score = 0.0, + group = 'headers', + parent = check_from_id, + type = 'virtual', + description = 'To address matches the From address', +} +rspamd_config:register_symbol { + name = 'TO_DOM_EQ_FROM_DOM', + score = 0.0, + group = 'headers', + parent = check_from_id, + type = 'virtual', + description = 'To domain is the same as the From domain', +} + +local check_to_cc_id = rspamd_config:register_symbol { + name = 'CHECK_TO_CC', + type = 'callback', + score = 0.0, + group = 'headers,mime', + callback = function(task) + local rcpts = task:get_recipients(1) + local to = task:get_recipients(2) + local to_match_envrcpt = 0 + local cnts = { + [1] = 'ONE', + [2] = 'TWO', + [3] = 'THREE', + [5] = 'FIVE', + [7] = 'SEVEN', + [12] = 'TWELVE', + [50] = 'GT_50' + } + local def = 'ZERO' + if (not to) then + return false + end + -- Add symbol for recipient count + local nrcpt = #to + for k, v in pairs(cnts) do + if nrcpt >= tonumber(k) then + def = v + end + end + task:insert_result('RCPT_COUNT_' .. def, 1.0, tostring(nrcpt)) + -- Check for display names + local to_dn_count = 0 + local to_dn_eq_addr_count = 0 + for _, toa in ipairs(to) do + -- To: Recipients <noreply@dropbox.com> + if (toa['name'] and (toa['name']:lower() == 'recipient' + or toa['name']:lower() == 'recipients')) then + task:insert_result('TO_DN_RECIPIENTS', 1.0) + end + if (toa['name'] and util.strequal_caseless(toa['name'], toa['addr'])) then + to_dn_eq_addr_count = to_dn_eq_addr_count + 1 + elseif (toa['name'] and toa['name'] ~= '') then + to_dn_count = to_dn_count + 1 + end + -- See if header recipients match envrcpts + if (rcpts) then + for _, rcpt in ipairs(rcpts) do + if (toa and toa['addr'] and rcpt and rcpt['addr'] and + util.strequal_caseless(rcpt['addr'], toa['addr'])) + then + to_match_envrcpt = to_match_envrcpt + 1 + end + end + end + end + if (to_dn_count == 0 and to_dn_eq_addr_count == 0) then + task:insert_result('TO_DN_NONE', 1.0) + elseif (to_dn_count == #to) then + task:insert_result('TO_DN_ALL', 1.0) + elseif (to_dn_count > 0) then + task:insert_result('TO_DN_SOME', 1.0) + end + if (to_dn_eq_addr_count == #to) then + task:insert_result('TO_DN_EQ_ADDR_ALL', 1.0) + elseif (to_dn_eq_addr_count > 0) then + task:insert_result('TO_DN_EQ_ADDR_SOME', 1.0) + end + + -- See if header recipients match envelope recipients + if (to_match_envrcpt == #to) then + task:insert_result('TO_MATCH_ENVRCPT_ALL', 1.0) + elseif (to_match_envrcpt > 0) then + task:insert_result('TO_MATCH_ENVRCPT_SOME', 1.0) + end + end +} + +rspamd_config:register_symbol { + name = 'RCPT_COUNT_ZERO', + score = 0.0, + parent = check_to_cc_id, + type = 'virtual', + description = 'No recipients', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'RCPT_COUNT_ONE', + score = 0.0, + parent = check_to_cc_id, + type = 'virtual', + description = 'One recipient', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'RCPT_COUNT_TWO', + score = 0.0, + parent = check_to_cc_id, + type = 'virtual', + description = 'Two recipients', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'RCPT_COUNT_THREE', + score = 0.0, + parent = check_to_cc_id, + type = 'virtual', + description = '3-5 recipients', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'RCPT_COUNT_FIVE', + score = 0.0, + parent = check_to_cc_id, + type = 'virtual', + description = '5-7 recipients', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'RCPT_COUNT_SEVEN', + score = 0.0, + parent = check_to_cc_id, + type = 'virtual', + description = '7-11 recipients', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'RCPT_COUNT_TWELVE', + score = 0.0, + parent = check_to_cc_id, + type = 'virtual', + description = '12-50 recipients', + group = 'headers', +} +rspamd_config:register_symbol { + name = 'RCPT_COUNT_GT_50', + score = 0.0, + parent = check_to_cc_id, + type = 'virtual', + description = '50+ recipients', + group = 'headers', +} + +rspamd_config:register_symbol { + name = 'TO_DN_RECIPIENTS', + score = 2.0, + group = 'headers', + parent = check_to_cc_id, + type = 'virtual', + description = 'To header display name is "Recipients"', +} +rspamd_config:register_symbol { + name = 'TO_DN_NONE', + score = 0.0, + group = 'headers', + parent = check_to_cc_id, + type = 'virtual', + description = 'None of the recipients have display names', +} +rspamd_config:register_symbol { + name = 'TO_DN_ALL', + score = 0.0, + group = 'headers', + parent = check_to_cc_id, + type = 'virtual', + description = 'All the recipients have display names', +} +rspamd_config:register_symbol { + name = 'TO_DN_SOME', + score = 0.0, + group = 'headers', + parent = check_to_cc_id, + type = 'virtual', + description = 'Some of the recipients have display names', +} +rspamd_config:register_symbol { + name = 'TO_DN_EQ_ADDR_ALL', + score = 0.0, + group = 'headers', + parent = check_to_cc_id, + type = 'virtual', + description = 'All of the recipients have display names that are the same as their address', +} +rspamd_config:register_symbol { + name = 'TO_DN_EQ_ADDR_SOME', + score = 0.0, + group = 'headers', + parent = check_to_cc_id, + type = 'virtual', + description = 'Some of the recipients have display names that are the same as their address', +} +rspamd_config:register_symbol { + name = 'TO_MATCH_ENVRCPT_ALL', + score = 0.0, + group = 'headers', + parent = check_to_cc_id, + type = 'virtual', + description = 'All of the recipients match the envelope', +} +rspamd_config:register_symbol { + name = 'TO_MATCH_ENVRCPT_SOME', + score = 0.0, + group = 'headers', + parent = check_to_cc_id, + type = 'virtual', + description = 'Some of the recipients match the envelope', +} + +-- TODO: rewrite this rule, it should not touch headers directly +rspamd_config.CTYPE_MISSING_DISPOSITION = { + callback = function(task) + local parts = task:get_parts() + if (not parts) or (parts and #parts < 1) then + return false + end + for _, p in ipairs(parts) do + local ct = p:get_header('Content-Type') + if (ct and ct:lower():match('^application/octet%-stream') ~= nil) then + local cd = p:get_header('Content-Disposition') + if (not cd) or (cd and cd:lower():find('^attachment') == nil) then + local ci = p:get_header('Content-ID') + if ci or (#parts > 1 and (cd and cd:find('filename=.+%.asc') ~= nil)) + then + return false + end + + local parent = p:get_parent() + + if parent then + local t, st = parent:get_type() + + if t == 'multipart' and st == 'encrypted' then + -- Special case + return false + end + end + + return true + end + end + end + return false + end, + description = 'Binary content-type not specified as an attachment', + score = 4.0, + group = 'mime' +} + +rspamd_config.CTYPE_MIXED_BOGUS = { + callback = function(task) + local ct = task:get_header('Content-Type') + if (not ct) then + return false + end + local parts = task:get_parts() + if (not parts) then + return false + end + if (not ct:lower():match('^multipart/mixed')) then + return false + end + local found = false + -- Check each part and look for a part that isn't multipart/* or text/plain or text/html + local ntext_parts = 0 + for _, p in ipairs(parts) do + local mtype, _ = p:get_type() + if mtype then + if mtype == 'text' and not p:is_attachment() then + ntext_parts = ntext_parts + 1 + if ntext_parts > 2 then + found = true + break + end + elseif mtype ~= 'multipart' then + found = true + break + end + end + end + if (not found) then + return true + end + return false + end, + description = 'multipart/mixed without non-textual part', + score = 1.0, + group = 'mime' +} + +local function check_for_base64_text(part) + local ct = part:get_header('Content-Type') + if (not ct) then + return false + end + ct = ct:lower() + if (ct:match('^text')) then + -- Check encoding + local cte = part:get_header('Content-Transfer-Encoding') + if (cte and cte:lower():match('^base64')) then + return true + end + end + return false +end + +rspamd_config.MIME_BASE64_TEXT = { + callback = function(task) + -- Check outer part + if (check_for_base64_text(task)) then + return true + else + local parts = task:get_parts() + if (not parts) then + return false + end + -- Check each part and look for base64 encoded text parts + for _, part in ipairs(parts) do + if (check_for_base64_text(part)) then + return true + end + end + end + return false + end, + description = 'Has text part encoded in base64', + score = 0.1, + group = 'mime' +} + +rspamd_config.MIME_BASE64_TEXT_BOGUS = { + callback = function(task) + local parts = task:get_text_parts() + if (not parts) then + return false + end + -- Check each part and look for base64 encoded text parts + -- where the part does not have any 8bit characters within it + for _, part in ipairs(parts) do + local mimepart = part:get_mimepart(); + if (check_for_base64_text(mimepart) and not part:has_8bit()) then + return true + end + end + return false + end, + description = 'Has text part encoded in base64 that does not contain any 8bit characters', + score = 1.0, + group = 'mime' +} + +local function is_8bit_addr(addr) + if addr.flags and addr.flags['8bit'] then + return true + end + + return false; +end + +rspamd_config.INVALID_FROM_8BIT = { + callback = function(task) + local from = (task:get_from('mime') or {})[1] or {} + if is_8bit_addr(from) then + return true + end + return false + end, + description = 'Invalid 8bit character in From header', + score = 6.0, + group = 'headers' +} + +rspamd_config.INVALID_RCPT_8BIT = { + callback = function(task) + local rcpts = task:get_recipients('mime') or {} + return fun.any(function(rcpt) + if is_8bit_addr(rcpt) then + return true + end + return false + end, rcpts) + end, + description = 'Invalid 8bit character in recipients headers', + score = 6.0, + group = 'headers' +} + +rspamd_config.XM_CASE = { + callback = function(task) + return task:has_header('X-mailer', true) + end, + description = 'X-mailer .vs. X-Mailer', + score = 0.5, + group = 'headers' +} |