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chore(yara): Log rule loading and check view section size #383

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Merged
rabbitstack merged 1 commit into from
Nov 22, 2024
Merged

chore(yara): Log rule loading and check view section size #383

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4 changes: 3 additions & 1 deletion pkg/yara/scanner.go
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Original file line number Diff line number Diff line change
Expand Up @@ -103,6 +103,7 @@ func NewScanner(psnap ps.Snapshotter, config config.Config) (Scanner, error) {
return nil
}
rulesInCompiler.Add(1)
log.Infof("loading yara rule(s) from %s", filepath.Join(path, fi.Name()))

return nil
})
Expand Down Expand Up @@ -277,7 +278,8 @@ func (s scanner) Scan(e *kevent.Kevent) (bool, error) {
// scan process mapping a suspicious RX/RWX section view
pid := e.Kparams.MustGetPid()
prot := e.Kparams.MustGetUint32(kparams.MemProtect)
if e.PID != 4 && ((prot&kevent.SectionRX) != 0 && (prot&kevent.SectionRWX) != 0) {
size := e.Kparams.MustGetUint64(kparams.FileViewSize)
if e.PID != 4 && size >= 4096 && ((prot&kevent.SectionRX) != 0 && (prot&kevent.SectionRWX) != 0) {
filename := e.GetParamAsString(kparams.FileName)
// skip mappings of signed images
addr := e.Kparams.MustGetUint64(kparams.FileViewBase)
Expand Down
4 changes: 4 additions & 0 deletions pkg/yara/scanner_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -725,6 +725,7 @@ func TestScan(t *testing.T) {
Kparams: kevent.Kparams{
kparams.ProcessID: {Name: kparams.ProcessID, Type: kparams.PID, Value: pid},
kparams.FileViewBase: {Name: kparams.FileViewBase, Type: kparams.Address, Value: uint64(0x7ffe0000)},
kparams.FileViewSize: {Name: kparams.FileViewSize, Type: kparams.Uint64, Value: uint64(12333)},
kparams.MemProtect: {Name: kparams.MemProtect, Type: kparams.Flags, Value: uint32(kevent.SectionRX), Flags: kevent.ViewProtectionFlags},
},
Metadata: make(map[kevent.MetadataKey]any),
Expand Down Expand Up @@ -780,6 +781,7 @@ func TestScan(t *testing.T) {
Kparams: kevent.Kparams{
kparams.ProcessID: {Name: kparams.ProcessID, Type: kparams.PID, Value: uint32(1123)},
kparams.FileViewBase: {Name: kparams.FileViewBase, Type: kparams.Address, Value: uint64(0x7f3e1000)},
kparams.FileViewSize: {Name: kparams.FileViewSize, Type: kparams.Uint64, Value: uint64(12333)},
kparams.MemProtect: {Name: kparams.MemProtect, Type: kparams.Flags, Value: uint32(kevent.SectionRX), Flags: kevent.ViewProtectionFlags},
},
Metadata: make(map[kevent.MetadataKey]any),
Expand Down Expand Up @@ -828,6 +830,7 @@ func TestScan(t *testing.T) {
Kparams: kevent.Kparams{
kparams.ProcessID: {Name: kparams.ProcessID, Type: kparams.PID, Value: uint32(321321)},
kparams.FileViewBase: {Name: kparams.FileViewBase, Type: kparams.Address, Value: uint64(0x7ffe0000)},
kparams.FileViewSize: {Name: kparams.FileViewSize, Type: kparams.Uint64, Value: uint64(12333)},
kparams.MemProtect: {Name: kparams.MemProtect, Type: kparams.Flags, Value: uint32(0x10000), Flags: kevent.ViewProtectionFlags},
},
Metadata: make(map[kevent.MetadataKey]any),
Expand Down Expand Up @@ -877,6 +880,7 @@ func TestScan(t *testing.T) {
kparams.ProcessID: {Name: kparams.ProcessID, Type: kparams.PID, Value: uint32(1123)},
kparams.FileName: {Name: kparams.FileName, Type: kparams.UnicodeString, Value: filepath.Join(os.Getenv("windir"), "regedit.exe")},
kparams.FileViewBase: {Name: kparams.FileViewBase, Type: kparams.Address, Value: uint64(0x7ffe0000)},
kparams.FileViewSize: {Name: kparams.FileViewSize, Type: kparams.Uint64, Value: uint64(12333)},
kparams.MemProtect: {Name: kparams.MemProtect, Type: kparams.Flags, Value: uint32(kevent.SectionRWX), Flags: kevent.ViewProtectionFlags},
},
Metadata: make(map[kevent.MetadataKey]any),
Expand Down
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