Microsoft Excel is prone to a remote code-execution vulnerability. Attackers may exploit this issue by enticing victims into opening a maliciously crafted Excel file. Successful exploits may allow attackers to execute arbitrary code with the privileges of the user running the application.
Run all software as a nonprivileged user with minimal access rights.
To reduce the impact of latent vulnerabilities, always run nonadministrative software as an unprivileged user with minimal access rights.
Do not accept or execute files from untrusted or unknown sources.
To reduce the likelihood of successful exploits, never handle files that originate from unfamiliar or untrusted sources.
Implement multiple redundant layers of security.
Various memory-protection schemes (such as nonexecutable and randomly mapped memory segments) may hinder an attacker's ability to exploit this vulnerability to execute arbitrary code.
Microsoft has released a security bulletin and fixes to address this vulnerability.