Internet Bug Bounty: Exim use-after-free vulnerability while reading mail header involving BDAT commands

Original article is here Use-after-free in receivemsg leads to RCE Vulnerability Analysis To explain this bug, we need to start with the memory management of exim. There is a series of functions starts with store such as storeget, storerelease, storereset. These functions are used to manage...

Exim 4.89 - 'BDAT' Denial of Service(CVE-2017-16944)

On 23 November, 2017, we reported two vulnerabilities to Exim. These bugs exist in the SMTP daemon and attackers do not need to be authenticated, including CVE-2017-16943 for a use-after-free UAF vulnerability, which leads to Remote Code Execution RCE; and CVE-2017-16944 for a Denial-of-Service D...

Exim 4.89 Denial Of Service

While parsing BDAT data header, exim still scans for '.' and consider it the end of mail. https://github.com/Exim/exim/blob/master/src/src/receive.cL1867 Exim goes into an incorrect state after this message is sent because the function pointer receivegetc is not reset. If the following command is...

UBUNTU-CVE-2017-16944

The receivemsg function in receive.c in the SMTP daemon in Exim 4.88 and 4.89 allows remote attackers to cause a denial of service infinite loop and stack exhaustion via vectors involving BDAT commands and an improper check for a '.' character signifying the end of the content, related to the...

exim -- remote code execution, deny of service in BDAT

Exim team reports: The receivemsg function in receive.c in the SMTP daemon in Exim 4.88 and 4.89 allows remote attackers to execute arbitrary code or cause a denial of service use-after-free via vectors involving BDAT commands...