Fix EXE/DLL cert verification#727
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val-ms merged 3 commits intoCisco-Talos:mainfrom Oct 22, 2022
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RSA certificate verification is failing because we accidentally lowered the max size of numbers for floating point multiplication with TomsFastMath when upgrading the vendored library code. This commit restores the default from 4096 to 8192.
The function `cli_scan_fmap()` is where we check PE authenticode certificates. But it is only returning CL_CLEAN, CL_VIRUS, or file types. It should propagate errors as well as CL_VERIFIED, if the authenticode finds we should trust the file.
The PE cert test can be enabled now that the cert trust feature is fixed. In so doing I found an issue with it -- it was also using the block-certificate signature, which overrides the trust-certificate signatures. This made me realize that we should also have a test to make sure the block-cert signatures take predence over the trust-cert sigs. I fixed the original sig and added this second test case.
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Backporting this one is too much pain. The recent allmatch fixes work cleaned up so much error handling that made this work reliably. Simply cherrypicking this fix does not cause certificate verification to correctly trust a file. A number of bugs exist causing it to continue scanning instead of aborting. Users will have to upgrade from 0.105 -> 1.0 for cert verification to work. |
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RSA certificate verification is failing because we accidentally lowered the max size of numbers for floating point multiplication with TomsFastMath when upgrading the vendored library code.
This commit restores the default from 4096 to 8192.
Fixes #604