Exim 4.70 - 4.80 DKIM DNS Record Parsing Remote Buffer Overflow
Medium Nessus Plugin ID 62734
SynopsisThe remote mail server is potentially affected by a buffer overflow vulnerability.
DescriptionAccording to its banner, the version of Exim running on the remote host is between 4.70 and 4.80 inclusive. It therefore is potentially affected by a remote, heap-based buffer overflow vulnerability when decoding DKIM (DomainKeys Identified Mail) DNS records that can be triggered by a specially crafted email sent from a domain under the attacker's control.
By exploiting this flaw, a remote, unauthenticated attacker could execute arbitrary code on the remote host subject to the privileges of the user running the affected application.
Note that this issue is only exploitable when exim is built with DKIM support, which is true by default, and has not been disabled. Note too that Nessus has not checked whether either condition is true.
SolutionUpgrade to Exim 4.80.1 or later.