usd-2019-0020 | Bitbucket/v5.10.1

Advisory ID: usd-2019-0020
CVE number: N/A
Affected Version: v5.10.1
Vulnerability Type: Sensitive Data in URL
Impact: Low
First Pubslished: 2019-07-31
Last Update: 2019-05-27

Details

Security Risk: Low
Vendor URL: https://www.atlassian.com/
Vendor Status: Not fixed
Advisory Status: Published

Introduction

Rather than directly attacking crypto, attackers steal keys, execute man-in-the-middle attacks or steal clear text data of the server while in transit or from the user’s client e.g. browser. A manual attack is generally required.

PoC

If an user changes his profile picture, the CSRF token is transfered inside the URL. The CSRF token does not change after that and is valid for the whole session.

Request:

POST /stash-kons/users/alice/avatar.png?atl_token=44df79fc27cf40a3ca9df08686400f095f242d92 HTTP/1.1
Host: hostname
Connection: close
Content-Length: 27979
Accept: */*
User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.109 Safari/537.36
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
Accept-Encoding: gzip, deflate
Accept-Language: en-US,en;q=0.9
Cookie: BITBUCKETSESSIONID=5DD59366F93308291C8EC6C0BCBF4184

[…]

Fix

Send the CSRF token as POST parameter.

Timeline

  • 2019-03-28 Vulnerability securily submitted to security@atlassian.com
  • 2019-04-11 Second contact attempt via contact formular
  • 2019-05-23 Atlassian Security Team agreed with the publishment of the advisory

Credits

This security vulnerabilities were found by Tobias Neitzel and Julian Frey of usd AG.

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In accordance with usd AG’s Responsible Disclosure Policy, all vendors have been notified of the existence of these vulnerabilities.

Disclaimer

The information provided in this security advisory is provided „as is“ and without warranty of any kind. Details of this security advisory may be updated in order to provide as accurate information as possible.