勒索病毒-特洛伊木马变种

​一、病毒简介 文件名称： 457d9e4773f45954449ee5913d068fdbb3d8e5689019688e7bce901467e5473a 文件类型(Magic)： PE32 executable (GUI) Intel 80386, for MS Windows, UPX compressed 文件大小： 410.00KB SHA256： 457d9e4773f45954449ee5913d068fdbb3d8e5689019688e7bce901467e5473a SHA1： eef83497e8aa02d644b7d071be81a678e1611aa6 MD5： adfacb09ceb60e6410e014275145b5a9 CRC32： 5BA85BCD SSDEEP： 6144:aR1d1ciOX8NFu7wOh06Y7/36SnEP9+xYzWVv/4oTQl+ds9qat4oCNGpLP/C7bIi:afd6iOMS7wOh0606j9iYz7fqAZp+E ImpHash： 6adb831a5884f7e68176214cc4749075 Tags： PE32,section_name_exception,encrypt_algorithm

二、环境准备 系统版本

win7x86

三、行为分析 在火绒里面添加信任区，然后打开火绒剑，开启监控：

简单做一下过滤：

首先看行为监控，有一个修改自启动项：

路径：“C:\Users\rkvir\AppData\Local\710d60a1-9877-43e7-a996-439fa0482755\病毒样本.exe” 这里是文件创建： !

这里是网络链接发包收包操作：

接下来这一块基本属于目录遍历，在每个文件夹下面生成readme.txt：

接下来是把很多文件后缀名加上了.litar：

当然还有设置文件安全属性为不可修改：

readme内容：

ATTENTION!

Don't worry, you can return all your files! All your files like photos, databases, documents and other important are encrypted with strongest encryption and unique key. The only method of recovering files is to purchase decrypt tool and unique key for you. This software will decrypt all your encrypted files. What guarantees you have? You can send one of your encrypted file from your PC and we decrypt it for free. But we can decrypt only 1 file for free. File must not contain valuable information. You can get and look video overview decrypt tool: https://we.tl/t-514KtsAKtH Price of private key and decrypt software is $980. Discount 50% available if you contact us first 72 hours, that's price for you is $490. Please note that you'll never restore your data without payment. Check your e-mail "Spam" or "Junk" folder if you don't get answer more than 6 hours.

To get this software you need write on our e-mail: gorentos@bitmessage.ch

Reserve e-mail address to contact us: varasto@firemail.cc

Our Telegram account: @datarestore

Your personal ID: 109AJsd73yiu3hjdfgiagsMxds3LxpDLrrIrIVlqmVQ2P4y09QCIrzCYt1

一个勒索病毒。

四、静态分析 首先拖入PEID，有UPX壳，先脱：

esp定律，这里不再多说。脱壳后拖入PEID查看：

随后拖入IDA中，开始分析：

捣鼓了半天，没找到病毒代码，动态调试一下。

五、动态分析 可以看到我们病毒样本都被修改，加了后缀名切无法恢复：

恢复快照，OD附加，顺带打开火绒剑监控：

前面和IDA中对照分析就好，到GetCommandLineA()这个函数的时候获取的是病毒路径：

从这里分析开始：

发现这里是关键函数：

完事我们发现了，这鬼东西又启动了自己，导致我们OD附加这个啥功能也不实现，用火绒剑再看一下：

接下来我们使用注册表一个调试操作，设置123.exe启动附加OD：

然后我们跑起第一次OD，结果如下：

然后我们OD成功附加启动的俩个123.exe：

可以看到再次启动桌面的123.exe主要是用来遍历目录生成readme.txt； 那么其他操作就是启动的C盘下的123.exe完成的。这里有点迷，我们重新看一下，找到了这块：

// write access to const memory has been detected, the output may be wrong! int sub_4032C0() { signed int v0; // esi@1 __int64 v1; // rax@2 int v2; // ecx@2 signed int v3; // esi@7 int v4; // ecx@11 DWORD flNewProtect; // [sp+30h] [bp-2224h]@7 int v7; // [sp+34h] [bp-2220h]@11 int v8; // [sp+38h] [bp-221Ch]@11 int v9; // [sp+50h] [bp-2204h]@11 int v10; // [sp+54h] [bp-2200h]@11 int v11; // [sp+5Ch] [bp-21F8h]@11 int v12; // [sp+60h] [bp-21F4h]@11 int v13; // [sp+64h] [bp-21F0h]@11 int v14; // [sp+74h] [bp-21E0h]@11 int v15; // [sp+78h] [bp-21DCh]@11 int v16; // [sp+7Ch] [bp-21D8h]@11 int v17; // [sp+84h] [bp-21D0h]@11 int v18; // [sp+8Ch] [bp-21C8h]@11 int v19; // [sp+94h] [bp-21C0h]@11 int v20; // [sp+98h] [bp-21BCh]@11 int v21; // [sp+A0h] [bp-21B4h]@11 int v22; // [sp+A8h] [bp-21ACh]@11 int v23; // [sp+B0h] [bp-21A4h]@11 int v24; // [sp+B8h] [bp-219Ch]@11 int v25; // [sp+C0h] [bp-2194h]@11 int v26; // [sp+C8h] [bp-218Ch]@11 int v27; // [sp+DCh] [bp-2178h]@11 int v28; // [sp+E0h] [bp-2174h]@11 int v29; // [sp+E8h] [bp-216Ch]@11 int v30; // [sp+F0h] [bp-2164h]@11 int v31; // [sp+F8h] [bp-215Ch]@11 int v32; // [sp+100h] [bp-2154h]@11 int v33; // [sp+108h] [bp-214Ch]@11 int v34; // [sp+110h] [bp-2144h]@11 int v35; // [sp+118h] [bp-213Ch]@11 int v36; // [sp+120h] [bp-2134h]@11 int v37; // [sp+134h] [bp-2120h]@11 int v38; // [sp+13Ch] [bp-2118h]@11 int v39; // [sp+144h] [bp-2110h]@11 int v40; // [sp+14Ch] [bp-2108h]@11 int v41; // [sp+154h] [bp-2100h]@11 int v42; // [sp+15Ch] [bp-20F8h]@11 int v43; // [sp+164h] [bp-20F0h]@11 int v44; // [sp+170h] [bp-20E4h]@11 int v45; // [sp+178h] [bp-20DCh]@11 int v46; // [sp+180h] [bp-20D4h]@11 int v47; // [sp+188h] [bp-20CCh]@11 int v48; // [sp+190h] [bp-20C4h]@11 int v49; // [sp+198h] [bp-20BCh]@11 int v50; // [sp+1A0h] [bp-20B4h]@11 DWORD dwProcessList; // [sp+1A4h] [bp-20B0h]@7 int v52; // [sp+1ACh] [bp-20A8h]@11 int v53; // [sp+1B0h] [bp-20A4h]@11 int v54; // [sp+1B8h] [bp-209Ch]@11 int v55; // [sp+1C0h] [bp-2094h]@11 int v56; // [sp+1C8h] [bp-208Ch]@11 int v57; // [sp+1D0h] [bp-2084h]@11 int v58; // [sp+1D8h] [bp-207Ch]@11 int v59; // [sp+1E0h] [bp-2074h]@11 int v60; // [sp+1E8h] [bp-206Ch]@11 int v61; // [sp+1FCh] [bp-2058h]@11 int v62; // [sp+204h] [bp-2050h]@11 int v63; // [sp+20Ch] [bp-2048h]@11 int v64; // [sp+214h] [bp-2040h]@11 int v65; // [sp+21Ch] [bp-2038h]@11 int v66; // [sp+220h] [bp-2034h]@11 int v67; // [sp+224h] [bp-2030h]@11 int v68; // [sp+228h] [bp-202Ch]@11 int v69; // [sp+22Ch] [bp-2028h]@11 int v70; // [sp+234h] [bp-2020h]@11 int v71; // [sp+23Ch] [bp-2018h]@11 int v72; // [sp+244h] [bp-2010h]@11 int v73; // [sp+24Ch] [bp-2008h]@11 int v74; // [sp+254h] [bp-2000h]@11 int v75; // [sp+25Ch] [bp-1FF8h]@11 int v76; // [sp+260h] [bp-1FF4h]@11 int v77; // [sp+264h] [bp-1FF0h]@11 int v78; // [sp+26Ch] [bp-1FE8h]@11 int v79; // [sp+274h] [bp-1FE0h]@11 int v80; // [sp+27Ch] [bp-1FD8h]@11 int v81; // [sp+284h] [bp-1FD0h]@11 int v82; // [sp+28Ch] [bp-1FC8h]@11 int v83; // [sp+294h] [bp-1FC0h]@11 int v84; // [sp+298h] [bp-1FBCh]@11 int v85; // [sp+29Ch] [bp-1FB8h]@11 int v86; // [sp+2A0h] [bp-1FB4h]@3 int v87; // [sp+2B0h] [bp-1FA4h]@11 int v88; // [sp+2B4h] [bp-1FA0h]@11 int v89; // [sp+2BCh] [bp-1F98h]@11 int v90; // [sp+2C4h] [bp-1F90h]@11 int v91; // [sp+2CCh] [bp-1F88h]@11 int v92; // [sp+2D4h] [bp-1F80h]@11 int v93; // [sp+2DCh] [bp-1F78h]@11 int v94; // [sp+2E4h] [bp-1F70h]@11 int v95; // [sp+2ECh] [bp-1F68h]@11 int v96; // [sp+2F4h] [bp-1F60h]@11 int v97; // [sp+2FCh] [bp-1F58h]@11 int v98; // [sp+304h] [bp-1F50h]@11 int v99; // [sp+30Ch] [bp-1F48h]@11 int v100; // [sp+314h] [bp-1F40h]@11 int v101; // [sp+31Ch] [bp-1F38h]@11 int v102; // [sp+324h] [bp-1F30h]@11 int v103; // [sp+32Ch] [bp-1F28h]@11 int v104; // [sp+334h] [bp-1F20h]@11 int v105; // [sp+33Ch] [bp-1F18h]@11 int v106; // [sp+344h] [bp-1F10h]@11 int v107; // [sp+348h] [bp-1F0Ch]@11 int v108; // [sp+34Ch] [bp-1F08h]@11 int v109; // [sp+354h] [bp-1F00h]@11 int v110; // [sp+35Ch] [bp-1EF8h]@11 int v111; // [sp+364h] [bp-1EF0h]@11 int v112; // [sp+36Ch] [bp-1EE8h]@11 int v113; // [sp+374h] [bp-1EE0h]@11 int v114; // [sp+37Ch] [bp-1ED8h]@11 int v115; // [sp+384h] [bp-1ED0h]@11 int v116; // [sp+38Ch] [bp-1EC8h]@11 int v117; // [sp+394h] [bp-1EC0h]@11 int v118; // [sp+3A4h] [bp-1EB0h]@11 int v119; // [sp+3ACh] [bp-1EA8h]@11 int v120; // [sp+3B4h] [bp-1EA0h]@11 int v121; // [sp+3BCh] [bp-1E98h]@11 int v122; // [sp+3C4h] [bp-1E90h]@11 int v123; // [sp+3CCh] [bp-1E88h]@11 __int64 v124; // [sp+3D0h] [bp-1E84h]@11 int v125; // [sp+3D8h] [bp-1E7Ch]@11 int v126; // [sp+404h] [bp-1E50h]@11 int v127; // [sp+40Ch] [bp-1E48h]@11 int v128; // [sp+414h] [bp-1E40h]@11 int v129; // [sp+41Ch] [bp-1E38h]@11 int v130; // [sp+424h] [bp-1E30h]@11 int v131; // [sp+42Ch] [bp-1E28h]@11 int v132; // [sp+434h] [bp-1E20h]@11 int v133; // [sp+43Ch] [bp-1E18h]@11 int v134; // [sp+444h] [bp-1E10h]@11 int v135; // [sp+44Ch] [bp-1E08h]@11 int v136; // [sp+454h] [bp-1E00h]@11 int v137; // [sp+45Ch] [bp-1DF8h]@11 int v138; // [sp+464h] [bp-1DF0h]@11 int v139; // [sp+46Ch] [bp-1DE8h]@11 int v140; // [sp+474h] [bp-1DE0h]@11 int v141; // [sp+47Ch] [bp-1DD8h]@11 int v142; // [sp+484h] [bp-1DD0h]@11 int v143; // [sp+48Ch] [bp-1DC8h]@11 int v144; // [sp+494h] [bp-1DC0h]@11 int v145; // [sp+49Ch] [bp-1DB8h]@11 int v146; // [sp+4A4h] [bp-1DB0h]@11 int v147; // [sp+4ACh] [bp-1DA8h]@11 int v148; // [sp+4B4h] [bp-1DA0h]@11 int v149; // [sp+4BCh] [bp-1D98h]@11 int v150; // [sp+4C4h] [bp-1D90h]@11 int v151; // [sp+4CCh] [bp-1D88h]@11 int v152; // [sp+4D4h] [bp-1D80h]@11 int v153; // [sp+4DCh] [bp-1D78h]@11 int v154; // [sp+4E4h] [bp-1D70h]@11 DWORD flOldProtect; // [sp+4E8h] [bp-1D6Ch]@11 int v156; // [sp+4ECh] [bp-1D68h]@11 int v157; // [sp+4F0h] [bp-1D64h]@11 int v158; // [sp+4F4h] [bp-1D60h]@11 int v159; // [sp+4F8h] [bp-1D5Ch]@11 int v160; // [sp+4FCh] [bp-1D58h]@11 int v161; // [sp+500h] [bp-1D54h]@11 int v162; // [sp+504h] [bp-1D50h]@11 int v163; // [sp+508h] [bp-1D4Ch]@11 int v164; // [sp+50Ch] [bp-1D48h]@11 int v165; // [sp+514h] [bp-1D40h]@11 int v166; // [sp+51Ch] [bp-1D38h]@11 int v167; // [sp+524h] [bp-1D30h]@11 int v168; // [sp+52Ch] [bp-1D28h]@11 int v169; // [sp+534h] [bp-1D20h]@11 int v170; // [sp+53Ch] [bp-1D18h]@11 int v171; // [sp+544h] [bp-1D10h]@11 int v172; // [sp+54Ch] [bp-1D08h]@11 int v173; // [sp+554h] [bp-1D00h]@11 int v174; // [sp+55Ch] [bp-1CF8h]@11 int v175; // [sp+564h] [bp-1CF0h]@11 int v176; // [sp+56Ch] [bp-1CE8h]@11 int v177; // [sp+574h] [bp-1CE0h]@11 int v178; // [sp+57Ch] [bp-1CD8h]@11 int v179; // [sp+580h] [bp-1CD4h]@11 int v180; // [sp+584h] [bp-1CD0h]@11 int v181; // [sp+588h] [bp-1CCCh]@11 int v182; // [sp+58Ch] [bp-1CC8h]@11 int v183; // [sp+594h] [bp-1CC0h]@11 int v184; // [sp+59Ch] [bp-1CB8h]@11 int v185; // [sp+5A4h] [bp-1CB0h]@11 int v186; // [sp+5ACh] [bp-1CA8h]@11 int v187; // [sp+5B4h] [bp-1CA0h]@11 int v188; // [sp+5BCh] [bp-1C98h]@11 int v189; // [sp+5C4h] [bp-1C90h]@11 int v190; // [sp+5C8h] [bp-1C8Ch]@11 int v191; // [sp+5CCh] [bp-1C88h]@11 int v192; // [sp+5D4h] [bp-1C80h]@11 struct _SYSTEM_INFO SystemInfo; // [sp+5E4h] [bp-1C70h]@2 int v194; // [sp+608h] [bp-1C4Ch]@11

v0 = 0; do { GetMessageTime(); GetLastError(); GetScrollBarInfo(0, 0, 0); GetNativeSystemInfo(&SystemInfo); if ( v0 > 1809073 ) { v1 = v86; if ( (v86 != 1610947977 || (unsigned __int64)v86 >> 32 != 2) && SystemInfo.dwProcessorType != 1718787859 ) break; } ++v0; } while ( v0 < 807178237 ); sub_401C10(v2, HIDWORD(v1)); dwProcessList = (DWORD)LocalAlloc(0, 0); lpAddress = (LPVOID)dwProcessList; dword_494D04 = 3859826; sub_4014C0(); flNewProtect = 64; v3 = 0; dword_489140 = 1852990827; dword_489147 = 1818504754; word_489145 = 13164; byte_489144 = 101; word_48914B = 108; do { if ( v3 == 149369 ) dword_494140 = (int)LoadLibraryW(L"kernel32.dll"); ++v3; } while ( v3 < 414547 ); dword_494D0A = 1635087474; dword_494D12 = 1952671092; dword_494D0E = 1869762668; word_494D08 = 26966; byte_494D16 = 0; VirtualProtect(0, 0, flNewProtect, &flOldProtect); v107 = 984736533; v194 = 300683120; v94 = 80588566; v117 = 1817873516; v157 = 500847454; v179 = 1567821180; v159 = 1302637794; v112 = 1102436357; v66 = 899399102; v89 = 2040936832; v52 = 481066167; v190 = 1841489596; v110 = 1320909356; v54 = 61576618; v58 = 1178734012; v161 = 1482589055; v181 = 298804231; v104 = 1400812470; v105 = 1196260586; v163 = 569189960; v126 = 801563110; v127 = 1457221645; v128 = 1225722463; v129 = 1834749888; v130 = 670996619; v131 = 1969515359; v132 = 1280972747; v133 = 780222590; v134 = 1565701075; v102 = 500443203; v135 = 65803943; v115 = 762364861; v136 = 795810006; v137 = 1123148568; v75 = 1586276094; v138 = 1272800795; v139 = 924921076; v140 = 1718812028; v141 = 1730685708; v142 = 2001956140; v143 = 733391458; v144 = 506360562; v145 = 1591939451; v146 = 1816995675; v147 = 1117439759; v148 = 2071161438; v149 = 1258081861; v150 = 487789358; v151 = 253059646; v152 = 1521776890; v153 = 1617526422; v154 = 1568020332; v156 = 1488928045; v158 = 420254226; v160 = 929234955; v162 = 434500457; v164 = 291757002; v165 = 1433345698; v166 = 1265348856; v167 = 59085654; v168 = 477351671; v169 = 1502814571; v170 = 708847487; v171 = 867103262; v172 = 1897004126; v173 = 1426888824; v174 = 604078171; v175 = 1657983563; v176 = 907912865; v177 = 334151250; v178 = 1807653057; v180 = 798053520; v182 = 2101597025; v183 = 1737159747; v184 = 2106467861; v185 = 1098556205; v186 = 934388979; v187 = 463230843; v188 = 161500149; v189 = 1707528495; v191 = 443682014; v192 = 806916367; v44 = 2015156112; v35 = 874317377; v125 = -1682276044; v37 = -539816070; v28 = 8361777; v11 = 1479804677; v84 = -1664213492; v38 = 47748601; v20 = -1786914781; v33 = -59558049; v14 = -1369878636; v39 = 703739348; v76 = 370184992; v47 = -1286993151; v87 = -440185045; v29 = -164279037; v88 = 953428873; v40 = 471044069; v90 = -621945634; v41 = -1649439383; v68 = 570423521; v78 = -396555381; v42 = 1354703776; v91 = 1053309223; v92 = -966288137; v93 = 948576792; v95 = 103542622; v16 = -160961522; v30 = 1887566721; v96 = 766532142; v31 = -341077087; v97 = -1585396389; v98 = 1996873759; v43 = 994006893; v99 = 1669983487; v19 = -1439980314; v71 = -1548404952; v53 = 826379314; v49 = -812990010; v32 = 1662205266; v12 = 272612147; v100 = -558352969; v101 = 1155305092; v69 = 885717425; v22 = 456490846; v55 = -1869724207; v45 = 1059130515; v103 = -102452497; v56 = -1166643018; v8 = 2097853817; v83 = 1543706697; v57 = 1469996252; v10 = 282560698; v46 = -441585956; v106 = -615454186; v108 = -111346605; v21 = 237988083; v13 = 523591549; v109 = 763210334; v36 = -1744225943; v111 = 95942471; v17 = -866671475; v59 = 1143821186; v60 = -1813524758; v61 = -624344467; v62 = -883867412; v113 = 2142616159; v114 = -456368282; v34 = 864555578; v116 = -154194316; v63 = 1089270003; v7 = -1425798802; v18 = 1413697337; v64 = 1701337139; v24 = -1306592042; v65 = 769109638; v67 = -197533786; v70 = 238612091; v118 = -1864660361; v9 = 1906236105; v85 = -1019740156; v23 = -1044823509; v72 = 1393427805; v48 = 1505955198; v15 = 1012219434; v73 = -1179555117; v74 = 113605890; v119 = 811375557; v50 = 1244845555; v120 = 190203595; v121 = 1974199582; v77 = -446442448; v79 = 1301378219; v80 = 1312276212; v122 = 290208957; v123 = 1184418735; v25 = -269624990; v81 = 649263029; v82 = 758748848; v27 = -1203314781; HIDWORD(v124) = -1497302171; v86 = 887858579; v26 = 1938448780; sub_401B00(v4); lpAddress = (LPVOID)2786; return ::v0(); }

结合之前第一次启动123.exe我们并没有看到什么效果，所以这段很可疑。接下来我们去OD跟随，跟进之前标记的关键函数那里：

跟进去很容易找到这里，就是前面我们看到IDA看到的地方：

找到下面，到virrtualproject函数这里，修改内存属性，找到参数地址，在数据区域找到，下内存断点，记录一下Address=0x002BEAD0,顺便下个内存断点:

这里对Address地址+0AE23.cn，然后call了shellcode地址：

我们跟进shellcode看看内容，首先是一段动态获取函数，一直跟到如下位置：

这里是对区段进行覆盖拷贝的一个操作。后面就是很大一坨动态加载函数的操作，然后修改启动项这些，拷贝自己，最后就是启动了新的程序，结束自己：

第一个123.exe也就是干了这么一件事。我们再看第二个，再次启动了一下他本身： 读取了很多后缀名exe的文件：

创建了SystemID和PersonalID.txt还有readme.txt的生成：

后面又对exe、txt、py、dat、udd、js等等后缀名的文件进行了重写和重命名：

然后一直运行，直至退出，所以第二次启动才是关键，我们停止第二个，清空监控列表，看看第三个：

同样是对文件读写重命名操作，但是会重复启动。接下来我们恢复快照追追第二个123.exe：

后续就是遍历目录生成readme.txt还有文件加密，这里不再多追。。。

六、结束语 主要是通过动态申请一段空间，放入shellcode，然后修改自己文件，进行校验，然后跳到开头执行，进行注册表启动，拷贝，网络链接等操作，然后重新启动自个，还有拷贝到c盘下的123.exe。主要加密功能由后续修改过得代码实现。

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