new file mode 100644
--- /dev/null
+++ b/ngx_http_catch_body_filter_module.c
@@ -0,0 +1,141 @@
+
+/*
+ * Copyright (C) Maxim Dounin
+ */
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_http.h>
+
+
+typedef struct {
+    ngx_flag_t         enable;
+} ngx_http_catch_body_conf_t;
+
+
+static void *ngx_http_catch_body_create_conf(ngx_conf_t *cf);
+static char *ngx_http_catch_body_merge_conf(ngx_conf_t *cf, void *parent,
+    void *child);
+static ngx_int_t ngx_http_catch_body_init(ngx_conf_t *cf);
+
+
+static ngx_command_t  ngx_http_catch_body_commands[] = {
+
+    { ngx_string("catch_body"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
+      ngx_conf_set_flag_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_catch_body_conf_t, enable),
+      NULL },
+
+      ngx_null_command
+};
+
+
+static ngx_http_module_t  ngx_http_catch_body_module_ctx = {
+    NULL,                          /* preconfiguration */
+    ngx_http_catch_body_init,      /* postconfiguration */
+
+    NULL,                          /* create main configuration */
+    NULL,                          /* init main configuration */
+
+    NULL,                          /* create server configuration */
+    NULL,                          /* merge server configuration */
+
+    ngx_http_catch_body_create_conf, /* create location configuration */
+    ngx_http_catch_body_merge_conf   /* merge location configuration */
+};
+
+
+ngx_module_t  ngx_http_catch_body_filter_module = {
+    NGX_MODULE_V1,
+    &ngx_http_catch_body_module_ctx, /* module context */
+    ngx_http_catch_body_commands,  /* module directives */
+    NGX_HTTP_MODULE,               /* module type */
+    NULL,                          /* init master */
+    NULL,                          /* init module */
+    NULL,                          /* init process */
+    NULL,                          /* init thread */
+    NULL,                          /* exit thread */
+    NULL,                          /* exit process */
+    NULL,                          /* exit master */
+    NGX_MODULE_V1_PADDING
+};
+
+
+static ngx_http_request_body_filter_pt   ngx_http_next_request_body_filter;
+
+
+static ngx_int_t
+ngx_http_catch_body_filter(ngx_http_request_t *r, ngx_chain_t *in)
+{
+    u_char                      *p;
+    ngx_chain_t                 *cl;
+    ngx_http_catch_body_conf_t  *conf;
+
+    conf = ngx_http_get_module_loc_conf(r, ngx_http_catch_body_filter_module);
+
+    if (!conf->enable) {
+        return ngx_http_next_request_body_filter(r, in);
+    }
+
+    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "catch request body filter");
+
+    for (cl = in; cl; cl = cl->next) {
+
+        p = cl->buf->pos;
+
+        for (p = cl->buf->pos; p < cl->buf->last; p++) {
+
+            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                           "catch body in:%02Xd:%c", *p, *p);
+
+            if (*p == 'X') {
+                ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                               "catch body: found");
+                return NGX_HTTP_FORBIDDEN;
+            }
+        }
+    }
+
+    return ngx_http_next_request_body_filter(r, in);
+}
+
+
+static void *
+ngx_http_catch_body_create_conf(ngx_conf_t *cf)
+{
+    ngx_http_catch_body_conf_t  *conf;
+
+    conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_catch_body_conf_t));
+    if (conf == NULL) {
+        return NULL;
+    }
+
+    conf->enable = NGX_CONF_UNSET;
+
+    return conf;
+}
+
+
+static char *
+ngx_http_catch_body_merge_conf(ngx_conf_t *cf, void *parent, void *child)
+{
+    ngx_http_catch_body_conf_t *prev = parent;
+    ngx_http_catch_body_conf_t *conf = child;
+
+    ngx_conf_merge_value(conf->enable, prev->enable, 0);
+
+    return NGX_CONF_OK;
+}
+
+
+static ngx_int_t
+ngx_http_catch_body_init(ngx_conf_t *cf)
+{
+    ngx_http_next_request_body_filter = ngx_http_top_request_body_filter;
+    ngx_http_top_request_body_filter = ngx_http_catch_body_filter;
+
+    return NGX_OK;
+}