3 ms·

The issue is not md5. The issue one wants to detect is weak hash functions used in cases where they're not appropriate. The fact that crc32 passed means that an

The issue is not md5. The issue one wants to detect is weak hash functions used in cases where they're not appropriate. The fact that crc32 passed means that any obscure hash function would have passed too, even if it had been used in a context were it isn't appropriate. All it means that the audit is superficial and doesn't catch the error category, just famous examples within that category. That kind of superficial sanning may be worth something when unleashed on security-naive developers or even as optional input for more experienced ones. But "hard compliance rules" and "superficial scans" combine to create a lot of busywork which makes people less motivated to work with auditors instead of against them.

meshaneian 6y ago
Next up: Replace MD5 with BASE64+ROT13. Significantly worse functionality AND performance, but sounds more secure (to a layman) and doesn't trigger the "MD5" alert...
- cortesoft 6y ago
  You joke, but an ex-security guy at my company literally told me “this file can’t be in plain text on disk. Base64 encode it”
  - skissane 6y ago
    Base64 encoding does protect somewhat against "looking over your shoulder" attacks (Unless the person looking over your shoulder has a really good memory and can remember the Base64, or decode it in their head. Or they have a camera.)
  - mschuster91 6y ago
    Helps against attackers grepping the whole disk (or any folder named "conf" or similar) for "username", "user", "password", "pass", "key" and friends. It's game over anyway if someone has a shell on your server but at least it complicates their life a bit.
theon144 6y ago
Both perspectives are somewhat correct, I feel; the requirement to remove any usage of md5 is beneficial, but the fact that crc32 passed means the audit shows the motivation was misplaced. The resulting situation might of course not be a net benefit though :/
dx034 6y ago
But way more people would use md5 for password hashing than crc32. Of course someone could circumvent these tests, but the risk of someone copying an old tutorial where md5 is used for password hashing can be mitigated.
jopsen 6y ago
> But "hard compliance rules" and "superficial scans" combine to create a lot of busywork which makes people less motivated to work with auditors instead of against them. Absolutely :) The fact is that if you have experienced engineers a security audit is rarely able to find anything. You would basically have to do code reviews, and this is hard / expensive, and even then rarely fruitful. So, superficial scans, hardening, checking for obvious mistakes is really all you can do. Making hard rules is unproductive, but then again, migrating from md5 to crc32 hopefully isn't very expensive. IMO, crc32 is a better choice for testing for changes, and has the benefit of removing any doubt that the hash has any security properties.

meshaneian 6y ago

Next up: Replace MD5 with BASE64+ROT13. Significantly worse functionality AND performance, but sounds more secure (to a layman) and doesn't trigger the "MD5" alert...

cortesoft 6y ago
You joke, but an ex-security guy at my company literally told me “this file can’t be in plain text on disk. Base64 encode it”
- skissane 6y ago
  Base64 encoding does protect somewhat against "looking over your shoulder" attacks (Unless the person looking over your shoulder has a really good memory and can remember the Base64, or decode it in their head. Or they have a camera.)
- mschuster91 6y ago
  Helps against attackers grepping the whole disk (or any folder named "conf" or similar) for "username", "user", "password", "pass", "key" and friends. It's game over anyway if someone has a shell on your server but at least it complicates their life a bit.

theon144 6y ago

Both perspectives are somewhat correct, I feel; the requirement to remove any usage of md5 is beneficial, but the fact that crc32 passed means the audit shows the motivation was misplaced. The resulting situation might of course not be a net benefit though :/

dx034 6y ago

But way more people would use md5 for password hashing than crc32. Of course someone could circumvent these tests, but the risk of someone copying an old tutorial where md5 is used for password hashing can be mitigated.

jopsen 6y ago

> But "hard compliance rules" and "superficial scans" combine to create a lot of busywork which makes people less motivated to work with auditors instead of against them. Absolutely :) The fact is that if you have experienced engineers a security audit is rarely able to find anything. You would basically have to do code reviews, and this is hard / expensive, and even then rarely fruitful. So, superficial scans, hardening, checking for obvious mistakes is really all you can do. Making hard rules is unproductive, but then again, migrating from md5 to crc32 hopefully isn't very expensive. IMO, crc32 is a better choice for testing for changes, and has the benefit of removing any doubt that the hash has any security properties.