Passive mode fails to parse http request responses: Could not read raw response .. malformed HTTP status code ...

[nil0x42]

Nuclei version:

2.7.1

Current Behavior:

nuclei passive mode completely fails to parse HTTP response if response body contains HTTP/1.1 string somewhere else.

Expected Behavior:

nuclei should correctly parse http responses.
when not possible, it should at least try to extract possible responses and match templates among all possibilities.

Steps To Reproduce:

I wrote a simple pastebin file here: https://pastebin.com/raw/TYsVwM0n, who can help reproduce the issue.

1. run proxify in a terminal
2. in other terminal, run curl --insecure -x 127.0.0.1:8888 'https://pastebin.com/raw/TYsVwM0n' to ask proxify to write the HTTP request/response file
3. a file like ./logs/pastebin.com*.txt has now been created by proxify
4. run nuclei -passive -target ./logs/pastebin.com*.txt

Nuclei sees a HTTP/1.1 in the body, completely stops considering the first (legitimate) HTTP/1.1, and displays the same error thousands time:

                     __     _
   ____  __  _______/ /__  (_)
  / __ \/ / / / ___/ / _ \/ /
 / / / / /_/ / /__/ /  __/ /
/_/ /_/\__,_/\___/_/\___/_/   2.7.1

                projectdiscovery.io

[WRN] Use with caution. You are responsible for your actions.
[WRN] Developers assume no liability and are not responsible for any misuse or damage.
[WRN] Found 2293 templates with runtime error (use -validate flag for further examination)
[INF] Using Nuclei Engine 2.7.1 (latest)
[INF] Using Nuclei Templates 9.0.2 (latest)
[INF] Templates added in last update: 24
[INF] Templates loaded for scan: 1038
[ERR] Could not read raw response pastebin.com:443-ca74m3uc7jlsd5a3vbp0.txt: malformed HTTP status code "FOO"
[ERR] Could not read raw response pastebin.com:443-ca74m3uc7jlsd5a3vbp0.txt: malformed HTTP status code "FOO"
[ERR] Could not read raw response pastebin.com:443-ca74m3uc7jlsd5a3vbp0.txt: malformed HTTP status code "FOO"
...
[ERR] Could not read raw response pastebin.com:443-ca74m3uc7jlsd5a3vbp0.txt: malformed HTTP status code "FOO"
[ERR] Could not read raw response pastebin.com:443-ca74m3uc7jlsd5a3vbp0.txt: malformed HTTP status code "FOO"
[ERR] Could not read raw response pastebin.com:443-ca74m3uc7jlsd5a3vbp0.txt: malformed HTTP status code "FOO"
[INF] No results found. Better luck next time!

For the record, here is the content of logs/pastebin/com*.txt on my computer:

GET /raw/TYsVwM0n HTTP/1.1
Host: pastebin.com
Accept: */*
User-Agent: curl/7.68.0

HTTP/1.1 200 OK
Transfer-Encoding: chunked
Cache-Control: max-age=1800, must-revalidate
Cf-Cache-Status: MISS
Cf-Ray: 710f4cc23fa97cc5-LAX
Connection: keep-alive
Content-Type: text/plain; charset=utf-8
Date: Wed, 25 May 2022 15:28:16 GMT
Expect-Ct: max-age=604800, report-uri="https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct"
Expires: Sat, 26 Jul 1997 05:00:00 GMT
Last-Modified: Wed, 25 May 2022 15:28:16 GMT
Pragma: no-cache
Server: cloudflare
Vary: Accept-Encoding
X-Content-Type-Options: nosniff
X-Frame-Options: DENY
X-Xss-Protection: 1;mode=block

38
line1
this is a line containing HTTP/1.1 FOO BAR
line3
0

[nil0x42]

Note that this issue actually arises more frequently than one could expect.
Indeed, any phpinfo output contains this string, as well as docs about http protocol.