private bool EnablesControlFlowGuard(BinaryAnalyzerContext context)
{
PEHeader peHeader = context.PE.PEHeaders.PEHeader;
if (((uint)peHeader.DllCharacteristics & IMAGE_DLLCHARACTERISTICS_CONTROLFLOWGUARD) == 0)
{
return(false);
}
SafePointer loadConfigRVA = new SafePointer(context.PE.ImageBytes, peHeader.LoadConfigTableDirectory.RelativeVirtualAddress);
if (loadConfigRVA.Address == 0)
{
return(false);
}
SafePointer loadConfigVA = context.PE.RVA2VA(loadConfigRVA);
if (context.PE.Is64Bit)
{
ImageLoadConfigDirectory64 loadConfig = new ImageLoadConfigDirectory64(peHeader, loadConfigVA);
Int32 imageDirectorySize = (Int32)loadConfig.GetField(ImageLoadConfigDirectory32.Fields.Size);
UInt64 guardCFCheckFunctionPointer = (UInt64)loadConfig.GetField(ImageLoadConfigDirectory64.Fields.GuardCFCheckFunctionPointer);
UInt64 guardCFFunctionTable = (UInt64)loadConfig.GetField(ImageLoadConfigDirectory64.Fields.GuardCFFunctionTable);
UInt32 guardFlags = (UInt32)loadConfig.GetField(ImageLoadConfigDirectory64.Fields.GuardFlags);
if (imageDirectorySize >= IMAGE_LOAD_CONFIG_MINIMUM_SIZE_64 &&
guardCFCheckFunctionPointer != 0 &&
guardCFFunctionTable != 0 &&
(guardFlags & IMAGE_GUARD_CF_CHECKS) == IMAGE_GUARD_CF_CHECKS)
{
return(true);
}
}
else
{
ImageLoadConfigDirectory32 loadConfig = new ImageLoadConfigDirectory32(peHeader, loadConfigVA);
Int32 imageDirectorySize = (Int32)loadConfig.GetField(ImageLoadConfigDirectory32.Fields.Size);
UInt32 guardCFCheckFunctionPointer = (UInt32)loadConfig.GetField(ImageLoadConfigDirectory32.Fields.GuardCFCheckFunctionPointer);
UInt32 guardCFFunctionTable = (UInt32)loadConfig.GetField(ImageLoadConfigDirectory32.Fields.GuardCFFunctionTable);
UInt32 guardFlags = (UInt32)loadConfig.GetField(ImageLoadConfigDirectory32.Fields.GuardFlags);
if (imageDirectorySize >= IMAGE_LOAD_CONFIG_MINIMUM_SIZE_32 &&
guardCFCheckFunctionPointer != 0 &&
guardCFFunctionTable != 0 &&
(guardFlags & IMAGE_GUARD_CF_CHECKS) == IMAGE_GUARD_CF_CHECKS)
{
return(true);
}
}
return(false);
}
private bool Validate64BitImage(BinaryAnalyzerContext context)
{
PEHeader peHeader = context.PE.PEHeaders.PEHeader;
SafePointer sp = new SafePointer(context.PE.ImageBytes, peHeader.LoadConfigTableDirectory.RelativeVirtualAddress);
SafePointer loadConfigVA = context.PE.RVA2VA(sp);
ImageLoadConfigDirectory64 loadConfig = new ImageLoadConfigDirectory64(peHeader, loadConfigVA);
UInt64 cookieVA = (UInt64)loadConfig.GetField(ImageLoadConfigDirectory64.Fields.SecurityCookie);
UInt64 baseAddress = peHeader.ImageBase;
// we need to find the offset in the file based on the cookie's VA
UInt64 sectionSize, sectionVA = 0;
SectionHeader ish = new SectionHeader();
bool foundCookieSection = false;
foreach (SectionHeader t in context.PE.PEHeaders.SectionHeaders)
{
sectionVA = (UInt64)(UInt32)t.VirtualAddress + baseAddress;
sectionSize = (UInt32)t.VirtualSize;
if ((cookieVA >= sectionVA) &&
(cookieVA < sectionVA + sectionSize))
{
ish = t;
foundCookieSection = true;
break;
}
}
if (!foundCookieSection)
{
LogCouldNotLocateCookie(context);
return(false);
}
UInt64 fileCookieOffset = (cookieVA - baseAddress) - (sectionVA - baseAddress) + (UInt32)ish.PointerToRawData;
SafePointer fileCookiePtr = loadConfigVA;
fileCookiePtr.Address = (int)fileCookieOffset;
UInt64 cookie = BitConverter.ToUInt64(fileCookiePtr.GetBytes(8), 0);
if (cookie != StackProtectionUtilities.DefaultCookieX64)
{
LogFailure(context, cookie.ToString("x"));
return(false);
}
return(true);
}
private bool Validate64BitImage(BinaryAnalyzerContext context)
{
PEBinary target = context.PEBinary();
PEHeader peHeader = target.PE.PEHeaders.PEHeader;
var sp = new SafePointer(target.PE.ImageBytes, peHeader.LoadConfigTableDirectory.RelativeVirtualAddress);
SafePointer loadConfigVA = target.PE.RVA2VA(sp);
var loadConfig = new ImageLoadConfigDirectory64(peHeader, loadConfigVA);
ulong cookieVA = (ulong)loadConfig.GetField(ImageLoadConfigDirectory64.Fields.SecurityCookie);
ulong baseAddress = peHeader.ImageBase;
// we need to find the offset in the file based on the cookie's VA
ulong sectionSize, sectionVA = 0;
var ish = new SectionHeader();
bool foundCookieSection = false;
foreach (SectionHeader t in target.PE.PEHeaders.SectionHeaders)
{
sectionVA = (uint)t.VirtualAddress + baseAddress;
sectionSize = (uint)t.VirtualSize;
if ((cookieVA >= sectionVA) &&
(cookieVA < sectionVA + sectionSize))
{
ish = t;
foundCookieSection = true;
break;
}
}
if (!foundCookieSection)
{
this.LogCouldNotLocateCookie(context);
return(false);
}
ulong fileCookieOffset = (cookieVA - baseAddress) - (sectionVA - baseAddress) + (uint)ish.PointerToRawData;
SafePointer fileCookiePtr = loadConfigVA;
fileCookiePtr.Address = (int)fileCookieOffset;
SafePointer boundsCheck = fileCookiePtr + 8;
if (!this.CookieOffsetValid(context, boundsCheck))
{
return(false);
}
if (!boundsCheck.IsValid && target.PE.IsPacked)
{
this.LogInvalidCookieOffsetForKnownPackedFile(context);
return(false);
}
ulong cookie = BitConverter.ToUInt64(fileCookiePtr.GetBytes(8), 0);
if (cookie != StackProtectionUtilities.DefaultCookieX64)
{
this.LogFailure(context, cookie.ToString("x"));
return(false);
}
return(true);
}
private bool Validate64BitImage(BinaryAnalyzerContext context)
{
PEHeader peHeader = context.PE.PEHeaders.PEHeader;
SafePointer sp = new SafePointer(context.PE.ImageBytes, peHeader.LoadConfigTableDirectory.RelativeVirtualAddress);
SafePointer loadConfigVA = context.PE.RVA2VA(sp);
ImageLoadConfigDirectory64 loadConfig = new ImageLoadConfigDirectory64(peHeader, loadConfigVA);
UInt64 cookieVA = (UInt64)loadConfig.GetField(ImageLoadConfigDirectory64.Fields.SecurityCookie);
UInt64 baseAddress = peHeader.ImageBase;
// we need to find the offset in the file based on the cookie's VA
UInt64 sectionSize, sectionVA = 0;
SectionHeader ish = new SectionHeader();
bool foundCookieSection = false;
foreach (SectionHeader t in context.PE.PEHeaders.SectionHeaders)
{
sectionVA = (UInt64)(UInt32)t.VirtualAddress + baseAddress;
sectionSize = (UInt32)t.VirtualSize;
if ((cookieVA >= sectionVA) &&
(cookieVA < sectionVA + sectionSize))
{
ish = t;
foundCookieSection = true;
break;
}
}
if (!foundCookieSection)
{
// '{0}' is a C or C++binary that enables the stack protection feature but the security cookie could not be located. The binary may be corrupted.
context.Logger.Log(MessageKind.Fail, context,
RuleUtilities.BuildMessage(context,
RulesResources.DoNotModifyStackProtectionCookie_CouldNotLocateCookie_Fail));
return(false);
}
UInt64 fileCookieOffset = (cookieVA - baseAddress) - (sectionVA - baseAddress) + (UInt32)ish.PointerToRawData;
SafePointer fileCookiePtr = loadConfigVA;
fileCookiePtr.Address = (int)fileCookieOffset;
UInt64 cookie = BitConverter.ToUInt64(fileCookiePtr.GetBytes(8), 0);
if (cookie != StackProtectionUtilities.DefaultCookieX64)
{
// '{0}' is a C or C++ binary that interferes with the stack protector. The
// stack protector (/GS) is a security feature of the compiler which makes
// it more difficult to exploit stack buffer overflow memory corruption
// vulnerabilities. The stack protector relies on a random number, called
// the "security cookie", to detect these buffer overflows. This 'cookie'
// is statically linked with your binary from a Visual C++ library in the
// form of the symbol __security_cookie. On recent Windows versions, the
// loader looks for the magic statically linked value of this cookie, and
// initializes the cookie with a far better source of entropy -- the system's
// secure random number generator -- rather than the limited random number
// generator available early in the C runtime startup code. When this symbol
// is not the default value, the additional entropy is not injected by the
// operating system, reducing the effectiveness of the stack protector. To
// resolve this issue, ensure that your code does not reference or create a
// symbol named __security_cookie or __security_cookie_complement. NOTE:
// the modified cookie value detected was: {1}
context.Logger.Log(MessageKind.Fail, context,
RuleUtilities.BuildMessage(context,
RulesResources.DoNotModifyStackProtectionCookie_Fail, cookie.ToString("x")));
return(false);
}
return(true);
}
