Vulnerabilidades de Scrapy

Scrapy is a high-level web crawling and scraping framework for Python. From 1.4.0 until 2.14.2, RefererMiddleware in scrapy/spidermiddlewares/referer.py treated a Referrer-Policy response-header value that resembled a Python import path as a referrer policy class, imported the referenced object, and called it. A malicious website could supply a callable such as sys.exit and terminate a crawler processing the response. This issue is fixed in version 2.14.2.

Scrapy is a high-level web crawling and scraping framework for Python. Prior to 2.17.0, in scrapy/core/downloader/handlers/s3.py, Scrapy's S3DownloadHandler converts an S3-scheme bucket and key request into a plaintext HTTP request to the corresponding S3 endpoint unless request.meta["is_secure"] is explicitly enabled, then signs and sends the plaintext request with configured AWS credentials. A network attacker who can observe traffic between Scrapy and S3 can read the bucket and key path, AWS Authorization header, X-Amz-Security-Token when temporary credentials are used, S3 object contents, and S3 response headers. An active man-in-the-middle attacker can also modify the plaintext S3 response body, status code, and headers before Scrapy processes them, causing scraped-data poisoning, poisoned exports, HTTP cache poisoning when caching is enabled, or influence over later crawl targets through forged redirects or attacker-controlled links. Users making S3-scheme requests with AWS credentials are affected. This issue is fixed in version 2.17.0.

Protego is a pure-Python robots.txt parser with support for modern conventions. Prior to 0.6.2, protego._urlpattern._URLPattern._prepare_pattern_for_regex translates every asterisk in an Allow or Disallow directive into a lazy regular-expression wildcard, so a directive containing many asterisks creates exponential backtracking. After protego.Protego.parse processes a crafted robots.txt file, protego.Protego.can_fetch can spend an attacker-controlled period matching a near-miss URL and deny service to the crawler. The vulnerable path is src/protego/_urlpattern.py in the _URLPattern match logic. This issue is fixed in version 0.6.2.

Scrapy versions up to 2.13.2 are vulnerable to a denial of service (DoS) attack due to a flaw in its brotli decompression implementation. The protection mechanism against decompression bombs fails to mitigate the brotli variant, allowing remote servers to crash clients with less than 80GB of available memory. This occurs because brotli can achieve extremely high compression ratios for zero-filled data, leading to excessive memory consumption during decompression.