发布日期：2012-07-07
更新日期：2012-07-10
受影响系统：
Check Point Software Abra
描述：
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BUGTRAQ ID: 54360
Check Point Abra可把一台普通PC变为受到全面保护的公司电脑。用户使用Abra，可随时随地、不论离线或在线，通过虚拟专用网（VPN）连接来访问公司电子邮件、文件和应用程序。Abra可在任何一台PC上自动运行，并且利用介质加密来保护U盘内的数据安全。
Check Point Abra在实现上存在安全限制绕过和信息泄露漏洞，成功利用后可允许攻击者获取敏感信息和绕过某些安全限制。
<*来源：Belov V.
Komarov A.
*>
测试方法：
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警 告
以下程序(方法)可能带有攻击性，仅供安全研究与教学之用。使用者风险自负！
Belov V. （）提供了如下测试方法：
Komarov A. （）提供了如下测试方法：
<Execute OriginalName="calc.exe" PathName="\calc.exe" AppName="Microsoft Calculator" UIDescription="Microsoft Calculator"/>
Application Control session examines the application run only on paths, file names, as well as record VersionInfo in the file.
This implies you can import an arbitrary application and run it to bypass the control policy of applications. This is implemented by changing the file name and the field in the resource OriginalFilename VERSIONINFO on any of the white list. Moreover, the user may replace any executable file (eg archiver WinRar) to the host OS without any imports into the secure session and the file will automatically be filled in a secure session (run by the correspondences of extensions, or from the "start" menu).
It is also possible to substitute the system default software from the session "Start" menu (Internet Explorer, Notepad, Calculator, File Protection is off to the host OS, you need administrator rights). The substitution of system files can be implemented after disabling File Protection Windows File Protection with a call to the fifth ordinal of exported file system sfc_os.dll functions (windows xp), sample code:
hInst := LoadLibrary('sfc_os.dll');
proc := GetProcAddress(hInst, ordinal 5);
filename := 'c:\windows\system32\calc.exe';
asm
push -1
push filename
push 0
call proc
end
Either by modifying the rights to the file (Vista and above):
takeown /f <имя_файла>
icacls <имя_файла> /grant %username%:F
icacls <имя_файла> /grant *S-1-1-0:(F)
It is also well executed Bat-files downloaded from the host computer?s folder called "Downloaded from PC", or any other.
The structure of the boot process and secure session:
During the secure session creates a separate process group. Executable files and libraries are the product of two assemblies 32 and 64-bit. But despite this, the 64-bit systems still run a few 32-bit modules in the X folder: \ Go \ PWC \ WoW64.
The second copy process launches the ISWMGR.exe Explorer explorer.exe processes, which is the parent of all, offered in a secure session of external tools and imported programs.
When starting the imported files in a secure session they run a separate application-boot X: \ PWC \ WOW64 \ ISWLDR.dat. He, in turn, loads the library ISWUL.dll, causing the function to set InitHook interceptions. Installed hooks calling functions for working with files, the registry, the clipboard, cryptography, etc:
HANDLE (__stdcall *__cdecl GetAddrOf_SetClipboardData())(UINT, HANDLE)
{
HANDLE (__stdcall *result)(UINT, HANDLE); // eax@1
result = SetClipboardData;
addr_SetClipboardData = SetClipboardData;
return result;
}
int __cdecl hooks_Clipboard()
{
int v0; // eax@1
int v1; // eax@3
int v2; // eax@5
int v3; // eax@7
int result; // eax@9
v0 = splice_func(addr_SetClipboardData, callback_SetClipboardData);
if ( v0 )
addr_SetClipboardData = v0;
v1 = splice_func(addr_GetClipboardData, callback_GetClipboardData);
if ( v1 )
addr_GetClipboardData = v1;
v2 = splice_func(addr_OpenClipboard, callback_OpenClipboard);
if ( v2 )
addr_OpenClipboard = v2;
v3 = splice_func(addr_EmptyClipboard, callback_EmptyClipboard);
if ( v3 )
addr_EmptyClipboard = v3;
result = splice_func(addr_CloseClipboard, callback_CloseClipboard);
if ( result )
addr_CloseClipboard = result;
return result;
}