Critical vulnerabilities in 6 AWS services disclosed at Black Hat USA
1–10 of 21 posts
Re: Critical vulnerabilities in 6 AWS services disclosed at Black Hat USA
#2For those who don't have the time to read the entire thing.
The “Shadow Resources” attack vector, which has since been addressed by AWS, stemmed from the automatic generation of S3 buckets by various AWS services, including:
- CloudFormation
- Glue
- EMR
- SageMaker
- ServiceCatalog
- CodeStar
Re: Critical vulnerabilities in 6 AWS services disclosed at Black Hat USA
#3I was expecting some obscure bug in signature verification or something but nope it’s a basic tempfile attack, the sort most of us learned how to avoid in shell scripts decades ago.
Re: Critical vulnerabilities in 6 AWS services disclosed at Black Hat USA
#4I was expecting some obscure bug in signature verification or something but nope it’s a basic tempfile attack, the sort most of us learned how to avoid in shell scripts decades ago.
Sadly I've barely been writing shell scripts for multiple decades, so needed to look this up.
> If an attacker pre-creates the file with relaxed access permissions, then data stored in the temporary file by the application may be accessed, modified or corrupted by an attacker.
https://owasp.org/www-community/vulnerabilities/Insecure_Tem...
Re: Critical vulnerabilities in 6 AWS services disclosed at Black Hat USA
#5For those who don't have the time to read the entire thing. The “Shadow Resources” attack vector, which has since been addressed by AWS, stemmed from the automatic generation of S3 buckets by various AWS services, including: - CloudFormation - Glue - EMR - SageMaker - ServiceCatalog - CodeStar
One interesting snippet is:
> [...] the researchers note that their findings demonstrate the importance of treating potential identifiers, such as AWS account IDs, as secrets
Which seems to be pretty opposite to the prevailing opinion, at least in some circles. For example the comments here [0] about how to get the account ID for an arbitrary S3 bucket, where many said it was essentially a nothing burger, similar to IP's or emails.
Regardless of who is correct, I think it's a telling example of the "dangers" with identifiers that are kinda-public-kinda-private. I'm guessing at least part of the root cause of this bug are AWS engineer's not thinking about the fact that account ID's aren't fully private.
Re: Critical vulnerabilities in 6 AWS services disclosed at Black Hat USA
#6I’m surprised it took AWS ~4 months to fully resolve the vulnerabilities…
Re: Critical vulnerabilities in 6 AWS services disclosed at Black Hat USA
#7I’m surprised it took AWS ~4 months to fully resolve the vulnerabilities…
Not sure I'm really surprised. As far as I know, AWS hasn't been the fastest in resolving issues. I just remember the "S3 Bucket - We Charge You For Unauthorized Requests" issue a few months ago
Re: Critical vulnerabilities in 6 AWS services disclosed at Black Hat USA
#8I’m surprised it took AWS ~4 months to fully resolve the vulnerabilities…
It has been 3 years since I reported a problem in one of their services and they still haven't found anyone who seems to even be able to understand the problem.
Re: Critical vulnerabilities in 6 AWS services disclosed at Black Hat USA
#9I’m surprised it took AWS ~4 months to fully resolve the vulnerabilities…
It has been 3 years since I reported a problem in one of their services and they still haven't found anyone who seems to even be able to understand the problem.
If it’s been 3 years since you reported a vulnerability, they’ve done nothing, and you can confirm the vulnerability still exists, you should tell the public about it since you’ve done your part as far as responsible disclosure is concerned—the public should know.
Re: Critical vulnerabilities in 6 AWS services disclosed at Black Hat USA
#10Though Amazon has protection against confused deputies for Principals , even within an account (every principal has a unique ID, and is account scoped), it doesn't have the same for Resources.
And s3 buckets are not scoped to an account and their ARN is global and doesn't contain the account id.
For the same reason i advice anybody to always use random suffixes (easily done in Terraform with name_prefix) when generating bucket names.