APM LDAP by path

Shoot. Sorry I misunderstood the internal writeup on this. Instead of not escaping itself it looks like it expects *you* to escape it manually. Can you try setting it to "\66\69\65\6C\64\3D\2A"? That should be "field=*". 

You're going to have to double-escape them inside the iRule or policy agent config. TCL gets weird with escaping sometimes. The example I've got from bigip.conf where the variable is being set from a var-assign policy agent to "medusademo" to formulate a search filter is:

apm policy agent variable-assign /Common/ldaptest_act_variable_assign_ag {
    variables {
        {
            expression "expr { \"\\\\59\\\\87\\\\FB\\\\A6\\\\AB\\\\1E\\\\D7\\\\40\\\\BE\\\\F8\\\\C7\\\\66\\\\C7\\\\DE\\\\CD\\\\56\" }"
            varname session.objectguid.foo
        }
    }
}

apm policy agent aaa-ldap /Common/ldap_query_bar_act_ldap_query_ag {
    filter "objectGUID=%{session.objectguid.foo}"
    search-dn cn=users,dc=lab,dc=apm,dc=f5test,dc=local
    server /Common/ldapQATest4
    type query
}

 If it doesn't work at first, packet capture a plaintext LDAP query so you can see what it's sending on the wire, the escaping might not be exactly right.