55 lines
1.5 KiB
Text
55 lines
1.5 KiB
Text
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rule korlia
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{
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meta:
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author = "Nick Hoffman "
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company = "Morphick"
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information = "korlia malware found in apt dump"
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ref = "http://www.morphick.com/resources/lab-blog/curious-korlia"
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//case a
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//b2 1f mov dl, 0x1f ; mov key (wildcard)
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// -----------------
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//8A 86 98 40 00 71 mov al, byte ptr url[esi]
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//BF 98 40 00 71 mov edi, offset url
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//32 C2 xor al, dl
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//83 C9 FF or ecx, 0FFFFFFFFh
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//88 86 98 40 00 71 mov byte ptr url[esi], al
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//33 C0 xor eax, eax
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//46 inc esi
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//F2 AE repne scasb
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//F7 D1 not ecx
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//49 dec ecx
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//3B F1 cmp esi, ecx
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//72 DE jb short loc_71001DE0
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//case b (variant of loop a)
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//8A 8A 28 50 40 00 mov cl, byte_405028[edx]
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//BF 28 50 40 00 mov edi, offset byte_405028
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//32 CB xor cl, bl
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//33 C0 xor eax, eax
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//88 8A 28 50 40 00 mov byte_405028[edx], cl
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//83 C9 FF or ecx, 0FFFFFFFFh
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//42 inc edx
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//F2 AE repne scasb
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//F7 D1 not ecx
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//49 dec ecx
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//3B D1 cmp edx, ecx
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//72 DE jb short loc_4047F2
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//case c (not a variant of the above loop)
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//8A 0C 28 mov cl, [eax+ebp]
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//80 F1 28 xor cl, 28h
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//88 0C 28 mov [eax+ebp], cl
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//8B 4C 24 14 mov ecx, [esp+0D78h+var_D64]
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//40 inc eax
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//3B C1 cmp eax, ecx
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//7C EE jl short loc_404F1C
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strings:
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$a = {b2 ?? 8A 86 98 40 00 71 BF 98 40 00 71 32 c2 83 C9 FF 88 86 98 40 00 71 33 C0 46 F2 AE F7 D1 49 3B F1}
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$b = {B3 ?? ?? ?? 8A 8A 28 50 40 00 BF 28 50 40 00 32 CB 33 C0 88 8A 28 50 40 00 83 C9 FF 42 F2 AE F7 D1 49 3B D1}
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$c = {8A 0C 28 80 F1 ?? 88 0C 28 8B 4C 24 14 40 3B C1}
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$d = {00 62 69 73 6F 6E 61 6C 00} //config marker "\x00bisonal\x00"
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condition:
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any of them
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}
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