Affected Products:![](https://publications.lexmark.com/media/ids_assets/images/transparent.png)
Single-Function: C748, C792, C925, and C950
Multifunction: X548, X746, X748, X792, X925, X950, X952, and X954
![](https://publications.lexmark.com/media/ids_assets/images/transparent.png)
Issue Description:
Smart card users are unable to authenticate after installing Windows updates containing protections for CVE-2020-33764 on supported Active Directory domain controllers.
![](https://publications.lexmark.com/media/ids_assets/images/transparent.png)
Solution:
Edit the krb5.conf file to remove "pkinit_win2k = yes"
![](https://publications.lexmark.com/media/ids_assets/images/transparent.png)
View the Current Kerberos file: Settings > Security > Security Setup > Kerberos 5 > View > Save the Kerberos File onto Notepad or WordPad.
![](https://publications.lexmark.com/media/ids_assets/images/transparent.png)
Replace the encryption lines with the following:
default_etypes = aes256-cts-hmac-sha1-96 aes128-cts-hmac-sha1-96 arcfour-hmac-md5 des-cbc-md5 des-cbc-crc
default_etypes_des = aes256-cts-hmac-sha1-96 aes128-cts-hmac-sha1-96 arcfour-hmac-md5 des-cbc-md5 des-cbc-crc
![](https://publications.lexmark.com/media/ids_assets/images/transparent.png)
Remove the "pkinit_win2k = yes" line from the file.
![](https://publications.lexmark.com/media/ids_assets/images/transparent.png)
Save the File as "AES256_KerberosFile.conf".
![](https://publications.lexmark.com/media/ids_assets/images/transparent.png)
Upload to device: Settings > Security > Security Setup > Kerberos 5 > Import Kerberos File.
![](https://publications.lexmark.com/media/ids_assets/images/transparent.png)
Change the PKI Authentication App or Smart Card Authentication Application to use Device Kerberos Setup.
Note: If the step is not followed, the Kerberos file will be reset to default settings and the changes applied will be lost.
![](https://publications.lexmark.com/media/ids_assets/images/transparent.png)
Still Need Help?
Have the following available when calling Lexmark Technical Support;
Printer model(s)
Printer serial number
LEGACY ID: SO9059