libdayzero.dll in the Filter Hub Service (filter-hub.exe) in Symantec Mail Security for SMTP before 5.0.1 Patch 181 and Mail Security Appliance before 5.0.0-36 allows remote attackers to cause a denial of service (crash) via a crafted executable attachment in an e-mail, involving the detection of "PE-Shield v0.2" and "ASPack v1.00-1.08.02".