平时接触到的 python 项目并不多,对 python 的代码审计更是没有接触,偶然朋友发来了一个漏洞 Flask send_file函数导致的绝对路径遍历 ,感觉打开了新世界的大门,于是就以一个初学者的角度,进行复现分析一下。详情也可以根据 Python : Flask Path Traversal Vulnerability 进行分析学习
from flask import Flask
from flask import send_file
app = Flask(__name__)
@app.route('/download')
def downloadFile():
path = "test.txt"
return send_file(path)
if __name__ == '__main__':
app.run()
from flask import Flask
from flask import send_file
app = Flask(__name__)
@app.route('/download')
def downloadFile():
path ="test.txt"
return send_file(path, as_attachment=True)
if__name__=='__main__':
app.run()
当下载的文件名是中文时
from flask import Flask
from flask import send_file
app = Flask(__name__)
@app.route('/download')
def downloadFile():
path ="测试.txt"
return send_file(path, as_attachment=True)
if__name__=='__main__':
app.run()
我们在本地构造一个简单的语句进行尝试
>>>import os.path >>> _root_path ="path/to/mySafeStaticDir" >>> path_or_file ="/../../../../../../../etc/passwd" >>> os.path.join(_root_path,path_or_file) '/../../../../../../../etc/passwd'
from flask import Flask, request
from flask import send_file
app = Flask(__name__)
@app.route('/download')
def downloadFile():
filename = request.args.get('filename')
return send_file(filename, as_attachment=True)
if__name__=='__main__':
app.run()
通过控制 filename 为绝对路径,就实现了目录穿越漏洞
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