Upgrade Nmap to OpenSSL version 1.1.1k

[fyodor]

We upgraded OpenSSL in the latest Nmap version 7.92 because that version fixes some CVE's. The vulnerabilities don't affect Nmap in a material way, but I still wanted to add this issue to document our (quick) research on these CVE's.

• CVE-2021-3450 - Nmap does not set the X509_V_FLAG_X509_STRICT flag, so this vulnerability is not applicable.
• CVE-2021-3449 - This issue affects ncat in listen mode with SSL enabled (ncat.exe -l --ssl). Nmap is not affected.
• CVE-2021-23841 - Nmap does not use the X509_issuer_and_serial_hash function, so this vulnerability is not applicable.
• CVE-2021-23840 - This vulnerability may affect certain NSE scripts and Nping in echo server or echo client mode. Ncat and all non-NSE Nmap features are unaffected. It would be a crash at worst.
• CVE-2020-1971 - Nmap does not do CRL verification, nor does any Nmap code call GENERAL_NAME_cmp or any TS_RESP_* API functions, so Nmap is unaffected.

[fyodor]

I'm closing this since we've upgraded to OpenSSL 1.1.1k in Nmap version 7.92.