The challenge URL is https://alternative.q.2020.volgactf.ru:7780/
The webpage just contains the text
>Hello there!Welcome to our first crypto challenge!Try to find some secret information here.
The site uses a selfsigned TLS certificate with the following content:
```Certificate:    Data:        Version: 3 (0x2)        Serial Number:            2f:56:ad:4c:98:83:f7:73:92:5e:1a:d5:e7:62:bb:05:f4:a8:8e:e7        Signature Algorithm: sha256WithRSAEncryption        Issuer: C = RU, ST = Samara, L = Samara, O = VolgaCTF, OU = CryptoGuys, CN = volgactf.ru        Validity            Not Before: Mar  7 05:46:24 2020 GMT            Not After : Mar  7 05:46:24 2022 GMT        Subject: C = RU, ST = Samara, L = Samara, O = VolgaCTF, OU = CryptoGuys, CN = volgactf.ru        Subject Public Key Info:            Public Key Algorithm: rsaEncryption                RSA Public-Key: (2048 bit)                Modulus:                    00:ab:20:5a:46:08:db:71:4c:23:5a:3c:88:12:05:                    84:94:e6:e3:43:c8:91:6d:d7:40:1d:a2:86:2c:a8:                    46:c2:92:b7:2e:aa:5c:21:19:ce:b9:30:f8:d3:b3:                    b2:48:52:fa:92:57:86:0b:e0:9e:b3:9d:39:bc:35:                    05:7d:94:f4:c0:10:42:0e:c2:3a:62:17:ec:5f:8c:                    a5:a2:ad:63:39:82:9c:74:f1:ae:6d:44:e4:dd:4a:                    c6:70:d9:15:86:e2:f8:df:09:62:4a:06:64:e8:21:                    35:ac:60:31:54:97:3d:e1:ef:b1:1d:87:bc:56:c6:                    d6:26:87:7f:3a:b5:1a:2c:56:61:e7:da:a6:d6:4f:                    de:78:fe:73:07:e8:2e:2e:bd:74:d1:bf:45:65:c1:                    fa:d1:0c:b2:f6:90:63:43:6d:ec:cb:b5:6e:70:69:                    00:7d:ca:f0:e5:77:20:b3:8d:c8:43:19:9f:23:bb:                    98:0d:b2:ae:ea:40:09:14:2e:0b:5e:2f:83:b3:16:                    d3:1c:f0:a2:39:a4:67:c7:76:c3:8d:23:6f:a3:49:                    41:64:ae:a5:6e:a4:4d:d1:09:a7:04:8b:00:78:ed:                    84:da:7a:5c:0e:ab:3c:3a:ff:9c:34:2c:5a:8d:c9:                    ae:3f:e2:c1:3e:3f:db:da:80:ed:c6:06:ad:98:e6:                    a9:a5                Exponent: 65537 (0x10001)        X509v3 extensions:            X509v3 Key Usage:                 Digital Signature, Non Repudiation, Key Encipherment            X509v3 Extended Key Usage:                 TLS Web Server Authentication            X509v3 Subject Alternative Name:                 DNS:www.volgactf.ru, DNS:s0.many.fields.in.certificate.com    Signature Algorithm: sha256WithRSAEncryption         51:dd:0b:0c:90:e0:81:a9:c9:42:90:cf:72:59:cb:d3:98:e5:         1e:ec:96:ee:d4:e1:eb:98:56:69:32:46:16:80:99:4c:3f:41:         ca:e2:e9:d9:7a:d8:a2:4d:eb:18:04:03:7b:a3:8e:c9:b5:e3:         b7:b5:c6:33:b9:8d:ac:76:e5:be:15:4e:6d:b5:14:64:72:2e:         02:96:c2:e7:d8:df:91:69:f2:ec:5b:8d:c2:be:99:c9:58:6a:         08:36:02:07:83:31:c0:75:88:bb:4b:e9:e2:e5:49:ae:35:63:         d4:7a:86:e7:78:73:cb:c3:db:3e:95:09:b9:b7:7a:9e:7a:77:         da:2a:09:66:b9:6e:c8:cd:62:b6:da:82:fd:63:43:1f:e7:9d:         8a:71:bc:a2:8d:68:bf:35:10:03:a8:cf:54:a8:ea:72:b2:a3:         cd:0c:7f:ce:6b:39:42:ad:45:c7:e6:28:6a:9b:3a:ab:45:8b:         47:df:f0:14:46:35:3c:b4:4f:ff:3b:62:4c:59:76:9a:2a:db:         98:97:57:f5:68:3e:32:f6:3a:45:7b:3f:c6:a2:45:79:f0:cf:         f7:64:39:90:61:7c:0a:92:37:d7:6e:fe:65:40:71:56:7f:5b:         b7:71:73:37:ab:82:22:3c:ee:8f:5c:48:1c:09:da:7a:5b:93:         6a:6a:a9:9e```
The second subject**Alternative**Name `s0.many.fields.in.certificate.com` looks interesting. After trying too many complicated things with it, I simply tried **VolgaCTF{s0.many.fields.in.certificate.com}** for the flag.