All,

An institutional vulnerability scan crashed 4D/Active4D last night.
We have A4D behind Apache, but based on my access logs and the 4D
crash report it looks like the scan my have passed in a query
parameter that gets base46 decoded. Here's the first part of the
crash thread:

Thread 15 Crashed:
0   libSystem.B.dylib                 0x926a94fe
__semwait_signal_nocancel + 10
1   libSystem.B.dylib                 0x926a93e2
nanosleep$NOCANCEL$UNIX2003 + 166
2   libSystem.B.dylib                 0x927242aa
usleep$NOCANCEL$UNIX2003 + 61
3   libSystem.B.dylib                 0x927459c8 abort + 105
4   icu                               0x1bd5ff5d 0x1bc01000 + 1437533
5   icu                               0x1bd11bc4 u_UCharsToChars_4_2
+ 126
6   com.aparajita.Active4D            0x1d84c6f3
plugin::crypto::base64Decode(plugin::Variable4D const&, char*&,
unsigned long&) + 167
7   com.aparajita.Active4D            0x1d8e8aa4
plugin::a4d::runtime::base64Decode(plugin::a4d::Interpreter&, void*)
+ 958
8   com.aparajita.Active4D            0x1d85d101
plugin::a4d::Interpreter::handleMethod(plugin::a4d::Interpreter::IdentifierInfo
const&) + 149
9   com.aparajita.Active4D            0x1d85d611
plugin::a4d::Interpreter::handleIdentifier(bool,
plugin::a4d::EToken&) + 279
10  com.aparajita.Active4D            0x1d860e8e
plugin::a4d::Interpreter::primary() + 1582
11  com.aparajita.Active4D            0x1d85fe58
plugin::a4d::Interpreter::expression() + 188
12  com.aparajita.Active4D            0x1d8bd093
plugin::a4d::Interpreter::getTextExpression()

The scan would have passed in text that would not have be base64
decode-able. They were trying to inject Javascript via a query
parameter.

I have not been able to replicate the crash, but am wondering if I
should filter untrusted input before passing it to base64 decode?

If so does anyone have a regex to use as a filter?

Aparajita,

If I can isolate a crash test case I'll file a bug report.

-- Brad
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