Yes, but only through brute-force. The one-way property of MD5 is still unbroken.Using the MD5 value of a user's email to access Gravatar is insecure and can lead to the leakage of user email.
This doesn't change a thing. You may as well brute-force SHA256 thus the information leakage remains the same.The official recommendation is to use SHA256 instead.
I'd recommend to switch to using HMAC (with SHA256 for good measure) as a keyed pseudo-random function here. When the secret ist kept - well - secret, negligible information about the user's email address is leaked. Performing brute-force without knowledge of the secret key is also not tractable.
Side note: This change does take away Gravatar's global property (i.e. across multiple sites). I can't think of a straightforward way to achieve global avatars without leaking any information about the user. However, if the goal here is to have a simple avatar picture this should be fine.
M. Sc. Fabian Bäumer Chair for Network and Data Security Ruhr University Bochum Universitätsstr. 150, Building MC 4/145 44780 Bochum Germany Am 25.09.24 um 08:28 schrieb Enxin Xie:
Severity: low Affected versions: - Apache Answer through 1.3.5 Description: Inadequate Encryption Strength vulnerability in Apache Answer. This issue affects Apache Answer: through 1.3.5. Using the MD5 value of a user's email to access Gravatar is insecure and can lead to the leakage of user email. The official recommendation is to use SHA256 instead. Users are recommended to upgrade to version 1.4.0, which fixes the issue. Credit: 张岳熙 (reporter) References: https://answer.incubator.apache.org https://www.cve.org/CVERecord?id=CVE-2024-40761
smime.p7s
Description: Kryptografische S/MIME-Signatur
