If you have some basic SQL and XML knowledge you can use SQLXML to query the packages for the ConnectionManager. ConnectionManger Info lives in DTS:ConnectionManger.
For example, if your SSIS packages were deployed to the package store in msdb you could get what you are looking for (or close to it) with this SQL query:
('www.microsoft.com/SqlServer/Dts' AS pNS1, 'www.microsoft.com/SqlServer/Dts' AS DTS) -- declare XML namespaces
package = c.name,
SELECT id, PackageXML = CAST(CAST(packagedata AS VARBINARY(MAX)) AS XML)
) AS PackageXML
CROSS APPLY PackageXML.nodes('/DTS:Executable/DTS:ConnectionManager') AS SSIS_XML(SSIS_XML)
JOIN msdb.dbo.sysssispackages AS c
ON PackageXML.id = c.id;
If you deploy to an SSIS catalog (SSISDB) then the FROM and namespace info will need to be updated accordingly. If you run the packages as .dtsx files then you would need to bring the files in using OPENROWSET or something similar.
"I cant stress enough the importance of switching from a sequential files mindset to set-based thinking. After you make the switch, you can spend your time tuning and optimizing your queries instead of maintaining lengthy, poor-performing code."
-- Itzik Ben-Gan 2001