Netgear Nighthawk R6700 Multiple Vulnerabilities

The following security-related issues have been found in the latest available firmware for the Nighthawk R6700v3 AC1750 consumer routing device (1.0.4.120 at the time of this writing).

Post Authentication Command Injection via SOAP Interface - CVE-2021-20173

We have identified 3 instances of unsanitized input being sent to system() calls in the upnpd binary, which runs by default.

The following request can be used to force an update check from the SOAP interface (note: this requires authenticating prior):

POST /soap/server_sa/ HTTP/1.0
SOAPAction: urn:NETGEAR-ROUTER:service:DeviceConfig:1#CheckNewFirmware
content-type: text/xml;charset=utf-8
HOST: routerlogin.net
User-Agent: SOAP Toolkit 3.0
Connection: close
Cache-Control: no-cache
Pragma: no-cache
Cookie: sess_id=018b49310551ca2de378a56e5f03294bc4c58e2b2dd8671d211abfbddaeb932dd8b60666d6c406356e71620c004fa226094ab2888d422f7133bf377490278819; SameSite=Strict
Content-Length: 525

<?xml version="1.0" encoding="UTF-8" standalone="no"?><SOAP-ENV:Envelope xmlns:SOAPSDK1="http://www.w3.org/2001/XMLSchema" xmlns:SOAPSDK2="http://www.w3.org/2001/XMLSchema-instance" xmlns:SOAPSDK3="http://schemas.xmlsoap.org/soap/encoding/" xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"><SOAP-ENV:Header><SessionID>E6A88AE69687E58D9A00</SessionID></SOAP-ENV:Header><SOAP-ENV:Body><M1:CheckNewFirmware xmlns:M1="urn:NETGEAR-ROUTER:service:DeviceConfig:1"></M1:CheckNewFirmware></SOAP-ENV:Body></SOAP-ENV:Envelope>

The following system() commands pull values from the device's configuration and run them directly on the device when the above request is sent:

Instance 1:
    snprintf(acStack640,0x200,
             "rm -f %s %s %s;wget -b --tries=2 --timeout=5 -o %s --ca-certificate /opt/xagent/certs/%s -O %s \'https://%s/%s/%s/%s\' &"
             ,"/tmp/stringtable.dat","/tmp/wget-log-upnp-strdat","/var/run/wget.pid",
             "/tmp/wget-log-upnp-strdat",&local_40,"/tmp/stringtable.dat",iVar1,acStack128,uVar2,
             uVar3);
    FUN_0000c310(3,"[upnp_sa] wget_SendGetStrDatCmd:%s\n",acStack640);
    system(acStack640);

Instance 2:
  snprintf(acStack712,0x200,
           "rm -f %s %s %s;wget -b --tries=2 --timeout=5 -o %s --ca-certificate /opt/xagent/certs/%s -O %s \'https://%s/%s/%s/%s\' &"
           ,"/tmp/firmwareCfg","/tmp/wget-log-upnp-finfo","/var/run/wget.pid",
           "/tmp/wget-log-upnp-finfo",&local_48,"/tmp/firmwareCfg",uVar1,acStack200,uVar2,uVar3);
  FUN_0000c310(3,"[upnp_sa] wget_SendGetCfgCmd:%s\n",acStack712);
  system(acStack712);

Instance 3:
    snprintf(acStack632,0x200,
             "rm -f %s %s %s;wget -b --tries=2 --timeout=5 -o %s --ca-certificate /opt/xagent/certs/%s -O %s https://%s/%s/%s/%s &"
             ,"/tmp/image.chk","/tmp/wget-log-upnp-img","/var/run/wget.pid","/tmp/wget-log-upnp-img"
             ,&local_38,"/tmp/image.chk",uVar1,acStack120,uVar2,&DAT_000c10d0);
    FUN_0000c310(3,"[upnp_sa] wget_SendGetImageCmd:%s\n",acStack632);
    system(acStack632);

Each of the above commands are executed when updates are checked for via the upnpd binary and can be injected with the corresponding configuration values. For example, by modifying the "ver_check_stringtable_dat" variable to use something like "stringtable.dat'; echo hi; #" will cause instance 1 to run "echo hi" when checking for updates. We have assigned a CVSS vector of CVSS:3.0/AV:A/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H to these issues.

Default HTTP Communication (Web Interface) - CVE-2021-20174

By default, all communication to/from the device's web interface is sent via HTTP, which causes potentially sensitive information (such as usernames and passwords) to be transmitted in cleartext. We recommend using HTTPS as the default.

CVSS score of CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N.

Default HTTP Communication (SOAP Interface) - CVE-2021-20175

By default, all communication to/from the device's SOAP Interface (port 5000) is sent via HTTP, which causes potentially sensitive information (such as usernames and passwords) to be transmitted in cleartext. We recommend using HTTPS as the default.

CVSS score of CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N.

Insufficient UART Protection Mechanisms - CVE-2021-23147

A malicious actor with physical access to the device is able to connect to the UART port via a serial connection and execute commands as the root user without authentication. We recommend disabling this UART console for production runs, or at least enforcing the same password mechanisms used for other functionality in the device (such as the web UI).

CVSS score of CVSS:3.0/AV: P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Configuration Manipulation via Hardcoded Encryption Routines - CVE-2021-45732

It does not appear that normal users are intended to be able to manipulate configuration backups due to the fact that they are encrypted/obfuscated. By extracting the configuration using readily available public tools, a user can reconfigure settings not intended to be manipulated, repackage the configuration, and restore a backup causing these settings to be changed.

CVSS score of CVSS:3.0/AV:A/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H.

Plaintext Password Storage - CVE-2021-45077

All usernames and passwords for the device's associated services are stored in plaintext on the device. For example, the admin password is stored in plaintext in the primary configuration file on the device.

CVSS score of CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.

Multiple Instances of Known Vulnerable jQuery Libraries

Several instances of jQuery libraries known to contain vulnerabilities are still in use (such as jquery 1.4.2). We recommend updating these instances to the latest available versions or ensuring that the vulnerable components are not in use.

Known Vulnerable minidlna.exe Service

The version of minidlna.exe running on the device contains publicly known vulnerabilities. We recommend upgrading to a more recent version.