<P class=MsoNormal><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">加殼往往是實現(xiàn)對原</SPAN><SPAN lang=EN-US>PE</SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的節(jié)數(shù)據(jù)加密、壓縮,若能加殼的同時,讓加殼后的程序調用殼中的某些子程序,那加殼強度大大增加。這樣處理后,即使脫掉了殼,程序執(zhí)行也肯定不正常,因為脫殼的同時也將這些子程序脫掉了!</SPAN><SPAN lang=EN-US> </SPAN></P>. f( n9 s# g. x9 p2 G) O) U
<P class=MsoNormal><SPAN lang=EN-US><SPAN style="mso-spacerun: yes"> </SPAN></SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">怎樣實現(xiàn)呢?作為探討性的介紹,還是搞一個最基本的來說(假設現(xiàn)在您已經(jīng)會寫</SPAN><SPAN lang=EN-US>PE-exe</SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">、</SPAN><SPAN lang=EN-US>PE-dll</SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">等</SPAN><SPAN lang=EN-US>PE</SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">加殼程序):</SPAN><SPAN lang=EN-US> </SPAN></P>
2 r i( v, `& h h<P class=MsoNormal><SPAN lang=EN-US><SPAN style="mso-spacerun: yes"> </SPAN></SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">我的實現(xiàn)是這樣的:作為一個</SPAN><SPAN lang=EN-US>PE</SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">文件,多多少少程序中會有</SPAN><SPAN lang=EN-US>mov eax,1</SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">或</SPAN><SPAN lang=EN-US>mov eax,0</SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的語句,就是從這里開刀,因為</SPAN><SPAN lang=EN-US>mov eax,xxxxxxxx</SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">這樣的指令長度正好與</SPAN><SPAN lang=EN-US>Call xxxxxxxx</SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">指令的長度一樣,處理起來相對簡單。在加殼程序加殼時,查找這些語句統(tǒng)統(tǒng)換成:</SPAN><SPAN lang=EN-US> </SPAN></P>1 u& \; K1 C. Z) M9 D7 `- |1 i. G
<P class=MsoNormal><SPAN lang=EN-US>call shellSub </SPAN></P>
5 X3 m& @. S$ E# ^" k$ ]1 J, v<P class=MsoNormal><SPAN lang=EN-US>// </SPAN></P>
( u2 m: b) t. h( @# O<P class=MsoNormal><SPAN lang=EN-US>shellSub</SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">實現(xiàn)如下:</SPAN><SPAN lang=EN-US> </SPAN></P>$ t* c) C( L5 y5 c' S+ G
<P class=MsoNormal><SPAN lang=EN-US>shellSub() </SPAN></P>6 k, A# P6 p0 n1 Z) O
<P class=MsoNormal><SPAN lang=EN-US>{ </SPAN></P>$ Z$ R$ B9 g+ h7 C" r! r0 L( l9 C' Z
<P class=MsoNormal><SPAN lang=EN-US><SPAN style="mso-spacerun: yes"> </SPAN>mov eax,1 </SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">或</SPAN><SPAN lang=EN-US> mov eax,0 </SPAN></P>8 P9 [. B& H; }/ w [: H2 h
<P class=MsoNormal><SPAN lang=EN-US>} </SPAN></P>
1 g3 k& Q7 w; n, V0 L<P class=MsoNormal><SPAN lang=EN-US><SPAN style="mso-spacerun: yes"> </SPAN></SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">當然,這里有個問題是怎樣計算這個</SPAN><SPAN lang=EN-US>Call xxxxxxxx</SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的</SPAN><SPAN lang=EN-US>xxxxxxxx</SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">,其實想一想也很簡單,加殼時候我們已經(jīng)計算出了外殼程序的入口</SPAN><SPAN lang=EN-US>RVA</SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">,只要以這個</SPAN><SPAN lang=EN-US>RVA</SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">為基準,就可以得到</SPAN><SPAN lang=EN-US>:(shellSub</SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的</SPAN><SPAN lang=EN-US>RVA)-(mov eax,1</SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的</SPAN><SPAN lang=EN-US>RVA)</SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的差值,這個差值再減去</SPAN><SPAN lang=EN-US>5</SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">(</SPAN><SPAN lang=EN-US>Call</SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">的指令長度)就是</SPAN><SPAN lang=EN-US>xxxxxxxx</SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">。</SPAN><SPAN lang=EN-US> </SPAN></P>
" D2 L' Y( D- {<P class=MsoNormal><SPAN lang=EN-US><SPAN style="mso-spacerun: yes"> </SPAN></SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">這里僅僅拋磚引玉的介紹了最基本的方法,其實通過變化,可以對原程序的很多特定語句實現(xiàn)改成調用外殼中不同的</SPAN><SPAN lang=EN-US>sub</SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">,大大增加了外殼的保密強度。</SPAN><SPAN lang=EN-US> </SPAN></P>
( E- F2 I( s9 b/ `<P class=MsoNormal><SPAN lang=EN-US><SPAN style="mso-spacerun: yes"> </SPAN></SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">這樣處理后,可想而知,脫殼后的運行情況:</SPAN><SPAN lang=EN-US>Windows</SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">錯誤,某個地址不能為讀或寫。。呵呵,要的就是這個效果?。?!</SPAN><SPAN lang=EN-US> </SPAN></P>2 m1 d3 Y" @9 \
<P class=MsoNormal><SPAN lang=EN-US><SPAN style="mso-spacerun: yes"> </SPAN></SPAN><SPAN style="FONT-FAMILY: 宋體; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'">錯誤之處,懇請各位高手指正!</SPAN><SPAN lang=EN-US> </SPAN></P> |