Coordinated Disclosure Timeline
- 2021-08-31: Followed the instructions in their security policy and entered the details into this form.
- 2021-08-31: Received automated email from notifications@erpnext.com after completing the form. Issue is tracked as
VUL-283348. - 2021-11-30: Deadline expired.
- 2021-12-06: Posted a pull request to fix the bug: https://github.com/frappe/frappe/pull/15201
Summary
Frappe contains a regular expression that is vulnerable to ReDoS (Regular Expression Denial of Service).
Product
Frappe
Tested Version
Details
ReDoS
ReDoS, or Regular Expression Denial of Service, is a vulnerability affecting inefficient regular expressions which can perform extremely badly when run on a crafted input string.
This vulnerability was found using a CodeQL query which identifies inefficient regular expressions. You can see the results of the query on Frappe by following this link.
Vulnerability
The vulnerable regular expression is here.
To see that the regular expression is vulnerable, copy-paste it into a separate file as shown below:
- Run the code below with
python3:
import re
re.match(r"^[\w][\w\'\-]*([ \w][\w\'\-]+)*$", "a'0'0'0'0'0'0'0'0'0'0'0'0'0'0'0'0'0'0'0'0'0'0'0'0'0'0'0'0'0'0'0'0'0}")
Impact
This issue may lead to a denial of service.
Credit
This issue was discovered by GitHub team members @erik-krogh (Erik Krogh Kristensen) and @yoff (Rasmus Petersen).
Contact
You can contact the GHSL team at securitylab@github.com, please include a reference to GHSL-2021-122 in any communication regarding this issue.