Cisco 2801 correct IOS for upgrade

[b.fratrik]

Hi,
our cisco routers 2801 are vulnerable to CSCtd75033. Current IOS version is 12.4(1c). Can you help me to find right IOS for upgrade?
Devices have 128 MB DRAM and 64 MB Flash. From download center looks fine for me version 12.4(19a). Software checker says no Cisco Security Advisories affect the selected software release. But I'm still on doubts if version 12.4(1c) is affected by CSCtd75033 or not. Thanks for advice.

 

[Leo Laohoo]

128 DRAM only?

Version 12.4(19a) is the obvious candidate but this version was first published 2008 and there are more sinister vulnerabilities on this firmware.  If there is no way of upgrading the DRAM then it's a no-brainer and risk getting hit with the NTP vulnerability than getting hit with the vulnerability found in 12.4(19a).  

Do the recommended workarounds will be the safe bet.