Hello,
Did a patch to handle bounce messages from backscatter attack with empty sender
address.
The filtering can be enabled using the following new options:
1. reject-sender-empty : turn on rejection of empty sender address
2. rejection-text-sender-empty : Rejection text when sender is empty
Here is the patch against 4.1.0 :
Index: spamdyke/spamdyke.c
===================================================================
--- spamdyke/spamdyke.c (revision 145)
+++ spamdyke/spamdyke.c (revision 147)
@@ -1328,6 +1328,14 @@
filter_sender_rhsbl(current_settings,
¤t_settings->current_options->filter_action,
¤t_settings->current_options->filter_action_locked,
¤t_settings->current_options->rejection,
¤t_settings->current_options->rejection_buf,
current_settings->current_options->reject_message_buf, MAX_BUF);
filter_sender_no_mx(current_settings,
¤t_settings->current_options->filter_action,
¤t_settings->current_options->filter_action_locked,
¤t_settings->current_options->rejection,
¤t_settings->current_options->rejection_buf,
current_settings->current_options->reject_message_buf, MAX_BUF);
}
+ } else if (current_settings->current_options->check_sender_empty) {
+ /* Check for missing sender */
+ current_settings->current_options->filter_action =
FILTER_DECISION_DO_FILTER;
+ set_rejection(current_settings, REJECTION_SENDER_EMPTY,
+ ¤t_settings->current_options->rejection,
¤t_settings->current_options->rejection_buf,
+ current_settings->current_options->reject_message_buf,
MAX_BUF);
+
+ SPAMDYKE_LOG_VERBOSE(current_settings,
LOG_VERBOSE_FILTER_SENDER_EMPTY);
}
if ((current_settings->current_options->filter_action ==
FILTER_DECISION_DO_FILTER) &&
Index: spamdyke/spamdyke.h
===================================================================
--- spamdyke/spamdyke.h (revision 145)
+++ spamdyke/spamdyke.h (revision 147)
@@ -551,6 +551,10 @@
#define ERROR_FAILURE_TLS "Failed to negotiate TLS connection."
#define FAILURE_DATA_TLS { FAILURE_TLS,
REJECT_SEVERITY_TLS_FAILURE, ERROR_FAILURE_TLS, STRLEN(ERROR_FAILURE_TLS),
"FAILED_TLS", 0 }
+#define REJECTION_SENDER_EMPTY 26
+#define ERROR_SENDER_EMPTY "Refused. Your sender address
is missing."
+#define REJECTION_DATA_SENDER_EMPTY { REJECTION_SENDER_EMPTY,
REJECT_SEVERITY_PERMANENT, ERROR_SENDER_EMPTY, STRLEN(ERROR_SENDER_EMPTY),
"DENIED_SENDER_EMPTY", 1 }
+
#define REJECTION_DATA (struct rejection_data []){ \
REJECTION_DATA_RCPT_TO, \
REJECTION_DATA_RCPT_TO_LOCAL, \
@@ -577,7 +581,8 @@
REJECTION_DATA_AUTH_REQUIRED, \
REJECTION_DATA_UNCONDITIONAL, \
REJECTION_DATA_IDENTICAL_FROM_TO, \
- FAILURE_DATA_TLS \
+ FAILURE_DATA_TLS, \
+ REJECTION_DATA_SENDER_EMPTY \
}
#define LOG_USE_CONFIG_TEST 0x01
@@ -805,6 +810,7 @@
#define LOG_VERBOSE_FILTER_SENDER_RHSBL "FILTER_RHSBL_MATCH domain: %s
rhsbl: %s"
#define LOG_VERBOSE_FILTER_SMTP_AUTH "FILTER_AUTH_REQUIRED"
#define LOG_VERBOSE_FILTER_SENDER_MX "FILTER_SENDER_NO_MX domain: %s"
+#define LOG_VERBOSE_FILTER_SENDER_EMPTY "FILTER_SENDER_EMPTY"
#define LOG_VERBOSE_FILTER_RECIPIENT_WHITELIST "FILTER_RECIPIENT_WHITELIST
recipient: %s entry: %s"
#define LOG_VERBOSE_FILTER_RECIPIENT_WHITELIST_FILE
"FILTER_RECIPIENT_WHITELIST recipient: %s file: %s(%d)"
#define LOG_VERBOSE_FILTER_RECIPIENT_LOCAL "FILTER_UNQUALIFIED_RECIPIENT
recipient: %s"
@@ -1385,6 +1391,7 @@
int check_rdns_exist;
int check_rdns_resolve;
int check_sender_mx;
+ int check_sender_empty;
int check_identical_from_to;
int timeout_connection;
Index: spamdyke/configuration.c
===================================================================
--- spamdyke/configuration.c (revision 145)
+++ spamdyke/configuration.c (revision 147)
@@ -1972,6 +1972,24 @@
CONFIG_TYPE_BOOLEAN,
CONFIG_ACCESS_NONE,
CONFIG_LOCATION_CMDLINE | CONFIG_LOCATION_GLOBAL_FILE |
CONFIG_LOCATION_DIR,
+ { "reject-sender-empty", optional_argument, NULL, -1 },
+ { .integer_value = 0 },
+ { .integer_value = 1 },
+ { .get_integer = CONFIG_ACCESSOR_INTEGER(check_sender_empty) },
+ { 0 },
+ FILTER_DECISION_UNDECIDED,
+ FILTER_GRACE_NONE,
+ NULL,
+ NULL,
+ NULL,
+ NULL,
+ "Check presence of sender's email address. If not found, reject the
connection."
+ " Default: do not check presence of sender's email."
+ },
+ {
+ CONFIG_TYPE_BOOLEAN,
+ CONFIG_ACCESS_NONE,
+ CONFIG_LOCATION_CMDLINE | CONFIG_LOCATION_GLOBAL_FILE |
CONFIG_LOCATION_DIR,
{ "reject-unresolvable-rdns", optional_argument, NULL, 'R' },
{ .integer_value = 0 },
{ .integer_value = 1 },
@@ -2242,6 +2260,7 @@
"TEXT",
"Use TEXT as the rejection message when a recipient is blocked because the
sender's email domain has no mail exchanger. Default: \"" ERROR_SENDER_NO_MX
"\""
},
+
{
CONFIG_TYPE_STRING_SINGLETON,
CONFIG_ACCESS_NONE,
@@ -2259,6 +2278,23 @@
"TEXT",
"Use TEXT as the rejection message when a connection is blocked because
the remote server's rDNS name is listed in a blacklist file or directory.
Default: \"" ERROR_BLACKLIST_NAME "\""
},
+ {
+ CONFIG_TYPE_STRING_SINGLETON,
+ CONFIG_ACCESS_NONE,
+ CONFIG_LOCATION_CMDLINE | CONFIG_LOCATION_GLOBAL_FILE |
CONFIG_LOCATION_DIR,
+ { "rejection-text-sender-empty", required_argument, NULL, -1 },
+ { .string_value = NULL },
+ { .string_value = NULL },
+ { .get_string =
CONFIG_ACCESSOR_STRING(rejection_text[REJECTION_SENDER_EMPTY]) },
+ { .max_strlen = 100 },
+ FILTER_DECISION_UNDECIDED,
+ FILTER_GRACE_NONE,
+ NULL,
+ NULL,
+ NULL,
+ "TEXT",
+ "Use TEXT as the rejection message when a recipient is blocked because
the sender's email is empty. Default: \"" ERROR_SENDER_EMPTY "\""
+ },
{
CONFIG_TYPE_STRING_SINGLETON,
CONFIG_ACCESS_NONE,
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