What you're experiencing is a common problem.  Vulnerability scanners that rely upon service banners do not deal with vendors like Red Hat which backport security updates.  They are also prone to making assumptions about configuration that lead to false positives.

You may be able to improve the accuracy of the scan by running an credentialed scan.  If your scanner supports it, you can specify account credentials that it will use to log in and look at "internal" information.  For example, it can use 'rpm' to determine which actual Apache package is installed, and base its verdict upon that rather than the banner that the service prints to external scanners.  Such a scanner should have access to an up-to-date database that will tell it what the real issues are.

If your scanner won't do it, then the usual solution is to do it yourself.  You would need to look up whether you're running the newest version.  For example, @Rook points out that there are Apache vulnerabilities newer than the package you reference.  Looking at those vulnerabilities, you can pull the CVE ID and look it up in Red Hat's CVE Database. For example, their entry for CVE-2013-1862 points you to the errata RHSA-2013:0815 which says that httpd-2.2.15-28 contains fixes for that CVE.  It also points out that there's a newer RHBA release, so there's a newer package with bug (but not security) fixes.  Repeat that process for any other CVEs that you're concerned with and you can make an educated decision about whether you're patched despite what the banner says.  If the CentOS package is a direct correlation to the RHEL package, you should be fine - but the RHEL package was announced on 5/13, so I don't know how @Rook's cited 3/2 release date jibes with that.

(The shortest version, BTW, is "yeah, this stuff is a known PITA.")

False positive Apache version in scanner results on Centos
In ME1 and ME2, I had to make decisions not really understanding their impact on the series as a whole.  Now that I'm partway through ME3, I find myself curious as to what would have happened had I made a different choice previously.  What if I'd done X?  What if I'd let Y live/die?

I can't just replay ME3, import my ME2 save, and make different choices to see these outcomes - I'd have to make changes to the way I played ME/ME2.  Likewise, importing no save would make wholesale changes to my experience that I'm not sure I'd appreciate.   

Besides starting the entire series over again, and running through each game dozens of times to explore the various permutations, what can I do to change the way things play out in ME3?  Do I get the option to edit the imported starting state on New Game+?

I'm on the Xbox, so save file editing or importing from the internet is likely to be at least challenging, if not impossible.  
