Rule request: `AvoidSecureStringDisclosure`

As for AvoidUsingConvertToSecureStringWithPlainText it should be avoided to retrieve a PlainText password from a SecureString as it might leave memory trials (or even logging trails).

$Password = $SecureString | ConvertFrom-SecureString -AsPlainText

Besides, the action that follows and requires the plaintext password is likely vulnerable from a security aspect.
This will also include the common used statements as:
(see: https://stackoverflow.com/a/28353003/1701026)

$SecurePassword = ConvertTo-SecureString $PlainPassword -AsPlainText -Force
$BSTR = [System.Runtime.InteropServices.Marshal]::SecureStringToBSTR($SecurePassword)
$Password = [System.Runtime.InteropServices.Marshal]::PtrToStringAuto($BSTR)
[Runtime.InteropServices.Marshal]::ZeroFreeBSTR($BSTR)

and (see: https://stackoverflow.com/a/40166959/1701026):

$Password = (New-Object PSCredential 0, $SecurePassword).GetNetworkCredential().Password

The general approach of dealing with credentials is to avoid them and instead rely on other means to authenticate, such as certificates or Windows authentication.

Proposed technical implementation details (optional)

Create rules to check for the above mentioned unsafe statements.

まず既存の PSScriptAnalyzer ルールの実装とテストを見つけ、ConvertFrom-SecureString、SecureStringToBSTR、PSC​​redential.GetNetworkCredential() の扱いを比較します。安全でない SecureString-to-plaintext パターンが確実に報告され、対応するアナライザーのテストが issue の例をカバーすれば、作業は完了です。