# xxe_upload_server.py - Uploads SVG, renders with lxml resolving entities
from flask import Flask, request
from lxml import etree
app = Flask(__name__)
@app.route('/upload', methods=['POST'])
def upload_svg():
svg_data = request.data
# Vulnerable: parses with entity resolution enabled
parser = etree.XMLParser(resolve_entities=True, no_network=False)
doc = etree.fromstring(svg_data, parser)
# Extract something from SVG
return etree.tostring(doc)
if __name__ == '__main__':
app.run(port=5000)
该 Web 应用接受 SVG 图片上传,并使用启用了外部实体解析的易受攻击的 XML 解析器进行解析。攻击者可以嵌入 XXE 载荷来读取本地文件、执行 SSRF 或造成拒绝服务。
resolve_entities=True 并允许网络访问,从而允许扩展外部实体。pip install flask lxml
python xxe_upload_server.py
python exploit_xxe_svg.py