<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(shí)現(xiàn)對(duì)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(shí),讓加殼后的程序調(diào)用殼中的某些子程序,那加殼強(qiáng)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?yàn)槊摎さ耐瑫r(shí)也將這些子程序脫掉了!</SPAN><SPAN lang=EN-US> </SPAN></P>6 ~- y- E2 w* }0 K
<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(shí)現(xiàn)呢?作為探討性的介紹,還是搞一個(gè)最基本的來(lái)說(shuō)(假設(shè)現(xiàn)在您已經(jīng)會(huì)寫(xiě)</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>! M/ x( y( u! B* x! M& y
<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(shí)現(xiàn)是這樣的:作為一個(gè)</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(huì)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(yǔ)句,就是從這里開(kāi)刀,因?yàn)?lt;/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(zhǎng)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(zhǎng)度一樣,處理起來(lái)相對(duì)簡(jiǎn)單。在加殼程序加殼時(shí),查找這些語(yǔ)句統(tǒng)統(tǒng)換成:</SPAN><SPAN lang=EN-US> </SPAN></P>2 V8 L: x2 f4 w5 m
<P class=MsoNormal><SPAN lang=EN-US>call shellSub </SPAN></P>
4 @5 y8 S' R& \+ d+ \<P class=MsoNormal><SPAN lang=EN-US>// </SPAN></P>
: J4 m9 p2 T4 y1 X4 l<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(shí)現(xiàn)如下:</SPAN><SPAN lang=EN-US> </SPAN></P>
4 U8 V4 E$ W) k<P class=MsoNormal><SPAN lang=EN-US>shellSub() </SPAN></P>$ P' k9 W! e* E: R$ @6 i, ^
<P class=MsoNormal><SPAN lang=EN-US>{ </SPAN></P>
" G! f- c+ q4 z9 n<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>4 `8 Y, B+ i, d6 ?% m' D
<P class=MsoNormal><SPAN lang=EN-US>} </SPAN></P>
: M1 k2 W/ G" h4 i* f2 B+ r2 _5 E# s6 T8 @<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(dāng)然,這里有個(gè)問(wèn)題是怎樣計(jì)算這個(gè)</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(shí)想一想也很簡(jiǎn)單,加殼時(shí)候我們已經(jīng)計(jì)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(gè)</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(zhǔn),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(gè)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(zhǎng)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>3 }& g: K. O# K4 b% H( g# O. K
<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(shí)通過(guò)變化,可以對(duì)原程序的很多特定語(yǔ)句實(shí)現(xiàn)改成調(diào)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(qiáng)度。</SPAN><SPAN lang=EN-US> </SPAN></P>7 D* f7 R' ]0 B- q( 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(yùn)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(cuò)誤,某個(gè)地址不能為讀或?qū)?。。呵呵,要的就是這個(gè)效果!??!</SPAN><SPAN lang=EN-US> </SPAN></P>- C8 `3 p$ w3 R
<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(cuò)誤之處,懇請(qǐng)各位高手指正!</SPAN><SPAN lang=EN-US> </SPAN></P> |