How To Get Information from Authenticode Signed Executables

CryptQueryObject.c

/*


# How To Get Information from Authenticode Signed Executables
https://support.microsoft.com/en-us/help/323809/how-to-get-information-from-authenticode-signed-executables

## Summary
You can use the WinVerifyTrust() API to verify an Authenticode signed executable. 

Although a signature is verified, a program may also have to do the following:
Determine the details of the certificate that signed the executable.
Determine the date and time that the file was time stamped.
Retrieve the URL link associated with the file.
Retrieve the timestamp certificate.
This article demonstrates how to use CryptQueryObject() API to retrieve detailed information from an Authenticode signed executable.1

## More Information
Authenticode signatures are PKCS7-based, therefore you can use CryptQueryObject and other Crypto API functions to retrieve the PKCS7 signature and to decode the PKCS7 attributes.

The following sample c code demonstrates how to use these APIs.

*/

#include <windows.h>
#include <wincrypt.h>
#include <wintrust.h>
#include <stdio.h>
#include <tchar.h>

#pragma comment(lib, "crypt32.lib")

#define ENCODING (X509_ASN_ENCODING | PKCS_7_ASN_ENCODING)

typedef struct {
    LPWSTR lpszProgramName;
    LPWSTR lpszPublisherLink;
    LPWSTR lpszMoreInfoLink;
} SPROG_PUBLISHERINFO, *PSPROG_PUBLISHERINFO;

BOOL GetProgAndPublisherInfo(PCMSG_SIGNER_INFO pSignerInfo,
                             PSPROG_PUBLISHERINFO Info);
BOOL GetDateOfTimeStamp(PCMSG_SIGNER_INFO pSignerInfo, SYSTEMTIME *st);
BOOL PrintCertificateInfo(PCCERT_CONTEXT pCertContext);
BOOL GetTimeStampSignerInfo(PCMSG_SIGNER_INFO pSignerInfo,
                            PCMSG_SIGNER_INFO *pCounterSignerInfo);

int _tmain(int argc, TCHAR *argv[])
{
    WCHAR szFileName[MAX_PATH];
    HCERTSTORE hStore = NULL;
    HCRYPTMSG hMsg = NULL;
    PCCERT_CONTEXT pCertContext = NULL;
    BOOL fResult;  
    DWORD dwEncoding, dwContentType, dwFormatType;
    PCMSG_SIGNER_INFO pSignerInfo = NULL;
    PCMSG_SIGNER_INFO pCounterSignerInfo = NULL;
    DWORD dwSignerInfo;
    CERT_INFO CertInfo;    
    SPROG_PUBLISHERINFO ProgPubInfo;
    SYSTEMTIME st;

    ZeroMemory(&ProgPubInfo, sizeof(ProgPubInfo));
    __try
    {
        if (argc != 2)
        {
            _tprintf(_T("Usage: SignedFileInfo <filename>\n"));
            return 0;
        }

#ifdef UNICODE
        lstrcpynW(szFileName, argv[1], MAX_PATH);
#else
        if (mbstowcs(szFileName, argv[1], MAX_PATH) == -1)
        {
            printf("Unable to convert to unicode.\n");
            __leave;
        }
#endif

        // Get message handle and store handle from the signed file.
        fResult = CryptQueryObject(CERT_QUERY_OBJECT_FILE,
            szFileName,
            CERT_QUERY_CONTENT_FLAG_PKCS7_SIGNED_EMBED,
            CERT_QUERY_FORMAT_FLAG_BINARY,
            0,
            &dwEncoding,
            &dwContentType,
            &dwFormatType,
            &hStore,
            &hMsg,
            NULL);
        if (!fResult)
        {
            _tprintf(_T("CryptQueryObject failed with %x\n"), GetLastError());
            __leave;
        }

        // Get signer information size.
        fResult = CryptMsgGetParam(hMsg,
            CMSG_SIGNER_INFO_PARAM,
            0,
            NULL,
            &dwSignerInfo);
        if (!fResult)
        {
            _tprintf(_T("CryptMsgGetParam failed with %x\n"), GetLastError());
            __leave;
        }

        // Allocate memory for signer information.
        pSignerInfo = (PCMSG_SIGNER_INFO)LocalAlloc(LPTR, dwSignerInfo);
        if (!pSignerInfo)
        {
            _tprintf(_T("Unable to allocate memory for Signer Info.\n"));
            __leave;
        }

        // Get Signer Information.
        fResult = CryptMsgGetParam(hMsg,
            CMSG_SIGNER_INFO_PARAM,
            0,
            (PVOID)pSignerInfo,
            &dwSignerInfo);
        if (!fResult)
        {
            _tprintf(_T("CryptMsgGetParam failed with %x\n"), GetLastError());
            __leave;
        }

        // Get program name and publisher information from
        // signer info structure.
        if (GetProgAndPublisherInfo(pSignerInfo, &ProgPubInfo))
        {
            if (ProgPubInfo.lpszProgramName != NULL)
            {
                wprintf(L"Program Name : %s\n",
                    ProgPubInfo.lpszProgramName);
            }

            if (ProgPubInfo.lpszPublisherLink != NULL)
            {
                wprintf(L"Publisher Link : %s\n",
                    ProgPubInfo.lpszPublisherLink);
            }

            if (ProgPubInfo.lpszMoreInfoLink != NULL)
            {
                wprintf(L"MoreInfo Link : %s\n",
                    ProgPubInfo.lpszMoreInfoLink);
            }
        }

        _tprintf(_T("\n"));

        // Search for the signer certificate in the temporary
        // certificate store.
        CertInfo.Issuer = pSignerInfo->Issuer;
        CertInfo.SerialNumber = pSignerInfo->SerialNumber;

        pCertContext = CertFindCertificateInStore(hStore,
            ENCODING,
            0,
            CERT_FIND_SUBJECT_CERT,
            (PVOID)&CertInfo,
            NULL);
        if (!pCertContext)
        {
            _tprintf(_T("CertFindCertificateInStore failed with %x\n"),
                GetLastError());
            __leave;
        }

        // Print Signer certificate information.
        _tprintf(_T("Signer Certificate:\n\n"));       
        PrintCertificateInfo(pCertContext);
        _tprintf(_T("\n"));

        // Get the timestamp certificate signerinfo structure.
        if (GetTimeStampSignerInfo(pSignerInfo, &pCounterSignerInfo))
        {
            // Search for Timestamp certificate in the temporary
            // certificate store.
            CertInfo.Issuer = pCounterSignerInfo->Issuer;
            CertInfo.SerialNumber = pCounterSignerInfo->SerialNumber;

            pCertContext = CertFindCertificateInStore(hStore,
                ENCODING,
                0,
                CERT_FIND_SUBJECT_CERT,
                (PVOID)&CertInfo,
                NULL);
            if (!pCertContext)
            {
                _tprintf(_T("CertFindCertificateInStore failed with %x\n"),
                    GetLastError());
                __leave;
            }

            // Print timestamp certificate information.
            _tprintf(_T("TimeStamp Certificate:\n\n"));
            PrintCertificateInfo(pCertContext);
            _tprintf(_T("\n"));

            // Find Date of timestamp.
            if (GetDateOfTimeStamp(pCounterSignerInfo, &st))
            {
                _tprintf(_T("Date of TimeStamp : %02d/%02d/%04d %02d:%02d\n"),
                    st.wMonth,
                    st.wDay,
                    st.wYear,
                    st.wHour,
                    st.wMinute);
            }
            _tprintf(_T("\n"));
        }
    }
    __finally
    {              
        // Clean up.
        if (ProgPubInfo.lpszProgramName != NULL)
            LocalFree(ProgPubInfo.lpszProgramName);
        if (ProgPubInfo.lpszPublisherLink != NULL)
            LocalFree(ProgPubInfo.lpszPublisherLink);
        if (ProgPubInfo.lpszMoreInfoLink != NULL)
            LocalFree(ProgPubInfo.lpszMoreInfoLink);

        if (pSignerInfo != NULL) LocalFree(pSignerInfo);
        if (pCounterSignerInfo != NULL) LocalFree(pCounterSignerInfo);
        if (pCertContext != NULL) CertFreeCertificateContext(pCertContext);
        if (hStore != NULL) CertCloseStore(hStore, 0);
        if (hMsg != NULL) CryptMsgClose(hMsg);
    }
    return 0;
}

BOOL PrintCertificateInfo(PCCERT_CONTEXT pCertContext)
{
    BOOL fReturn = FALSE;
    LPTSTR szName = NULL;
    DWORD dwData;

    __try
    {
        // Print Serial Number.
        _tprintf(_T("Serial Number: "));
        dwData = pCertContext->pCertInfo->SerialNumber.cbData;
        for (DWORD n = 0; n < dwData; n++)
        {
            _tprintf(_T("%02x "),
                pCertContext->pCertInfo->SerialNumber.pbData[dwData - (n + 1)]);
        }
        _tprintf(_T("\n"));

        // Get Issuer name size.
        if (!(dwData = CertGetNameString(pCertContext,
            CERT_NAME_SIMPLE_DISPLAY_TYPE,
            CERT_NAME_ISSUER_FLAG,
            NULL,
            NULL,
            0)))
        {
            _tprintf(_T("CertGetNameString failed.\n"));
            __leave;
        }

        // Allocate memory for Issuer name.
        szName = (LPTSTR)LocalAlloc(LPTR, dwData * sizeof(TCHAR));
        if (!szName)
        {
            _tprintf(_T("Unable to allocate memory for issuer name.\n"));
            __leave;
        }

        // Get Issuer name.
        if (!(CertGetNameString(pCertContext,
            CERT_NAME_SIMPLE_DISPLAY_TYPE,
            CERT_NAME_ISSUER_FLAG,
            NULL,
            szName,
            dwData)))
        {
            _tprintf(_T("CertGetNameString failed.\n"));
            __leave;
        }

        // print Issuer name.
        _tprintf(_T("Issuer Name: %s\n"), szName);
        LocalFree(szName);
        szName = NULL;

        // Get Subject name size.
        if (!(dwData = CertGetNameString(pCertContext,
            CERT_NAME_SIMPLE_DISPLAY_TYPE,
            0,
            NULL,
            NULL,
            0)))
        {
            _tprintf(_T("CertGetNameString failed.\n"));
            __leave;
        }

        // Allocate memory for subject name.
        szName = (LPTSTR)LocalAlloc(LPTR, dwData * sizeof(TCHAR));
        if (!szName)
        {
            _tprintf(_T("Unable to allocate memory for subject name.\n"));
            __leave;
        }

        // Get subject name.
        if (!(CertGetNameString(pCertContext,
            CERT_NAME_SIMPLE_DISPLAY_TYPE,
            0,
            NULL,
            szName,
            dwData)))
        {
            _tprintf(_T("CertGetNameString failed.\n"));
            __leave;
        }

        // Print Subject Name.
        _tprintf(_T("Subject Name: %s\n"), szName);

        fReturn = TRUE;
    }
    __finally
    {
        if (szName != NULL) LocalFree(szName);
    }

    return fReturn;
}

LPWSTR AllocateAndCopyWideString(LPCWSTR inputString)
{
    LPWSTR outputString = NULL;

    outputString = (LPWSTR)LocalAlloc(LPTR,
        (wcslen(inputString) + 1) * sizeof(WCHAR));
    if (outputString != NULL)
    {
        lstrcpyW(outputString, inputString);
    }
    return outputString;
}

BOOL GetProgAndPublisherInfo(PCMSG_SIGNER_INFO pSignerInfo,
                             PSPROG_PUBLISHERINFO Info)
{
    BOOL fReturn = FALSE;
    PSPC_SP_OPUS_INFO OpusInfo = NULL; 
    DWORD dwData;
    BOOL fResult;

    __try
    {
        // Loop through authenticated attributes and find
        // SPC_SP_OPUS_INFO_OBJID OID.
        for (DWORD n = 0; n < pSignerInfo->AuthAttrs.cAttr; n++)
        {          
            if (lstrcmpA(SPC_SP_OPUS_INFO_OBJID,
                pSignerInfo->AuthAttrs.rgAttr[n].pszObjId) == 0)
            {
                // Get Size of SPC_SP_OPUS_INFO structure.
                fResult = CryptDecodeObject(ENCODING,
                    SPC_SP_OPUS_INFO_OBJID,
                    pSignerInfo->AuthAttrs.rgAttr[n].rgValue[0].pbData,
                    pSignerInfo->AuthAttrs.rgAttr[n].rgValue[0].cbData,
                    0,
                    NULL,
                    &dwData);
                if (!fResult)
                {
                    _tprintf(_T("CryptDecodeObject failed with %x\n"),
                        GetLastError());
                    __leave;
                }

                // Allocate memory for SPC_SP_OPUS_INFO structure.
                OpusInfo = (PSPC_SP_OPUS_INFO)LocalAlloc(LPTR, dwData);
                if (!OpusInfo)
                {
                    _tprintf(_T("Unable to allocate memory for Publisher Info.\n"));
                    __leave;
                }

                // Decode and get SPC_SP_OPUS_INFO structure.
                fResult = CryptDecodeObject(ENCODING,
                    SPC_SP_OPUS_INFO_OBJID,
                    pSignerInfo->AuthAttrs.rgAttr[n].rgValue[0].pbData,
                    pSignerInfo->AuthAttrs.rgAttr[n].rgValue[0].cbData,
                    0,
                    OpusInfo,
                    &dwData);
                if (!fResult)
                {
                    _tprintf(_T("CryptDecodeObject failed with %x\n"),
                        GetLastError());
                    __leave;
                }

                // Fill in Program Name if present.
                if (OpusInfo->pwszProgramName)
                {
                    Info->lpszProgramName =
                        AllocateAndCopyWideString(OpusInfo->pwszProgramName);
                }
                else
                    Info->lpszProgramName = NULL;

                // Fill in Publisher Information if present.
                if (OpusInfo->pPublisherInfo)
                {

                    switch (OpusInfo->pPublisherInfo->dwLinkChoice)
                    {
                    case SPC_URL_LINK_CHOICE:
                        Info->lpszPublisherLink =
                            AllocateAndCopyWideString(OpusInfo->pPublisherInfo->pwszUrl);
                        break;

                    case SPC_FILE_LINK_CHOICE:
                        Info->lpszPublisherLink =
                            AllocateAndCopyWideString(OpusInfo->pPublisherInfo->pwszFile);
                        break;

                    default:
                        Info->lpszPublisherLink = NULL;
                        break;
                    }
                }
                else
                {
                    Info->lpszPublisherLink = NULL;
                }

                // Fill in More Info if present.
                if (OpusInfo->pMoreInfo)
                {
                    switch (OpusInfo->pMoreInfo->dwLinkChoice)
                    {
                    case SPC_URL_LINK_CHOICE:
                        Info->lpszMoreInfoLink =
                            AllocateAndCopyWideString(OpusInfo->pMoreInfo->pwszUrl);
                        break;

                    case SPC_FILE_LINK_CHOICE:
                        Info->lpszMoreInfoLink =
                            AllocateAndCopyWideString(OpusInfo->pMoreInfo->pwszFile);
                        break;

                    default:
                        Info->lpszMoreInfoLink = NULL;
                        break;
                    }
                }              
                else
                {
                    Info->lpszMoreInfoLink = NULL;
                }

                fReturn = TRUE;

                break; // Break from for loop.
            } // lstrcmp SPC_SP_OPUS_INFO_OBJID                
        } // for
    }
    __finally
    {
        if (OpusInfo != NULL) LocalFree(OpusInfo);     
    }

    return fReturn;
}

BOOL GetDateOfTimeStamp(PCMSG_SIGNER_INFO pSignerInfo, SYSTEMTIME *st)
{  
    BOOL fResult;
    FILETIME lft, ft;  
    DWORD dwData;
    BOOL fReturn = FALSE;

    // Loop through authenticated attributes and find
    // szOID_RSA_signingTime OID.
    for (DWORD n = 0; n < pSignerInfo->AuthAttrs.cAttr; n++)
    {          
        if (lstrcmpA(szOID_RSA_signingTime,
            pSignerInfo->AuthAttrs.rgAttr[n].pszObjId) == 0)
        {              
            // Decode and get FILETIME structure.
            dwData = sizeof(ft);
            fResult = CryptDecodeObject(ENCODING,
                szOID_RSA_signingTime,
                pSignerInfo->AuthAttrs.rgAttr[n].rgValue[0].pbData,
                pSignerInfo->AuthAttrs.rgAttr[n].rgValue[0].cbData,
                0,
                (PVOID)&ft,
                &dwData);
            if (!fResult)
            {
                _tprintf(_T("CryptDecodeObject failed with %x\n"),
                    GetLastError());
                break;
            }

            // Convert to local time.
            FileTimeToLocalFileTime(&ft, &lft);
            FileTimeToSystemTime(&lft, st);

            fReturn = TRUE;

            break; // Break from for loop.

        } //lstrcmp szOID_RSA_signingTime
    } // for

    return fReturn;
}

BOOL GetTimeStampSignerInfo(PCMSG_SIGNER_INFO pSignerInfo, PCMSG_SIGNER_INFO *pCounterSignerInfo)
{  
    PCCERT_CONTEXT pCertContext = NULL;
    BOOL fReturn = FALSE;
    BOOL fResult;      
    DWORD dwSize;  

    __try
    {
        *pCounterSignerInfo = NULL;

        // Loop through unathenticated attributes for
        // szOID_RSA_counterSign OID.
        for (DWORD n = 0; n < pSignerInfo->UnauthAttrs.cAttr; n++)
        {
            if (lstrcmpA(pSignerInfo->UnauthAttrs.rgAttr[n].pszObjId,
                szOID_RSA_counterSign) == 0)
            {
                // Get size of CMSG_SIGNER_INFO structure.
                fResult = CryptDecodeObject(ENCODING,
                    PKCS7_SIGNER_INFO,
                    pSignerInfo->UnauthAttrs.rgAttr[n].rgValue[0].pbData,
                    pSignerInfo->UnauthAttrs.rgAttr[n].rgValue[0].cbData,
                    0,
                    NULL,
                    &dwSize);
                if (!fResult)
                {
                    _tprintf(_T("CryptDecodeObject failed with %x\n"),
                        GetLastError());
                    __leave;
                }

                // Allocate memory for CMSG_SIGNER_INFO.
                *pCounterSignerInfo = (PCMSG_SIGNER_INFO)LocalAlloc(LPTR, dwSize);
                if (!*pCounterSignerInfo)
                {
                    _tprintf(_T("Unable to allocate memory for timestamp info.\n"));
                    __leave;
                }

                // Decode and get CMSG_SIGNER_INFO structure
                // for timestamp certificate.
                fResult = CryptDecodeObject(ENCODING,
                    PKCS7_SIGNER_INFO,
                    pSignerInfo->UnauthAttrs.rgAttr[n].rgValue[0].pbData,
                    pSignerInfo->UnauthAttrs.rgAttr[n].rgValue[0].cbData,
                    0,
                    (PVOID)*pCounterSignerInfo,
                    &dwSize);
                if (!fResult)
                {
                    _tprintf(_T("CryptDecodeObject failed with %x\n"),
                        GetLastError());
                    __leave;
                }

                fReturn = TRUE;

                break; // Break from for loop.
            }          
        }
    }
    __finally
    {
        // Clean up.
        if (pCertContext != NULL) CertFreeCertificateContext(pCertContext);
    }

    return fReturn;
}