Insufficient Input Validation in sendmail
Summary
DSA-1985-1: sendmail - insufficient input validation. Affects sendmail versions < 8.13.8-3+etch1. Fixed in 8.13.8-3+etch1. How to fix ↓
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Background
sendmail is a Mail Transport Agent (MTA) used for sending and receiving email messages. It is a widely used and trusted MTA in the Debian ecosystem. However, a vulnerability has been discovered in sendmail that allows an attacker to spoof SSL-based SMTP servers and bypass access restrictions.
Vulnerability Detail
The vulnerability in sendmail arises from its improper handling of a '\0' character in the Common Name (CN) field of an X.509 certificate. This flaw enables an attacker to create a crafted server certificate issued by a legitimate Certification Authority, thereby impersonating arbitrary SSL-based SMTP servers. Additionally, the vulnerability allows the attacker to create a crafted client certificate issued by a legitimate Certification Authority, bypassing intended access restrictions.
How To Fix
Minimum fixed version
8.13.8-3+etch1
This is the first release that contains the fix.
sudo apt-get install --only-upgrade sendmailTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
There is no specific workaround mentioned for this vulnerability.
Conclusion
The sendmail package is vulnerable to an insufficient input validation issue that allows attackers to spoof SSL-based SMTP servers and bypass access restrictions. It is recommended to upgrade the sendmail package to the fixed versions mentioned above. For further support on vulnerability remediation, please contact DevNack.com.
See every vulnerability recorded for sendmail →
FAQ
sendmail is a Mail Transport Agent (MTA) used for sending and receiving email messages.
This vulnerability allows an attacker to spoof SSL-based SMTP servers and bypass access restrictions.
To fix this vulnerability, upgrade the sendmail package to the recommended versions.
No specific workarounds have been mentioned for this vulnerability.
You can find more information about this vulnerability in the provided source link.
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