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I got published twice this year: Admin Magazine #25 and Linux User & Developer #155

Admin Magazine #25: Secure Programming Techniques

In February this year this article came out in the UK, EEUU and Australia. Its main focus is on the different modern protections available for GNU/Linux distributions to prevent malicious users from exploiting software flaws, like stack overflows and the like. Although it is, indeed, quite a […]

/var/log/btmp on Debian Wheezy is always empty (lastb does not show entries)

The issue

Whenever a bad login attempt is made against the Secure Shell daemon on a Debian GNU/Linux Wheezy, only /var/log/auth.log is filled. The file /var/log/btmp is always empty, therefore it is impossible to get the list of failed logins by means of running the lastb command.

Logging to /var/log/btmp is […]

Using gdb to solve yet more software-related problems

The issue

Opening a Microsoft Excel 2007+ spreadsheet in Libre Office Calc 3.5.4.2 Build ID: 350m1(Build:2) on a Debian Wheezy 64 bit fires a segmentation fault. The document contains three spreadsheets with some formulas and links between them.:

[936028.103160] soffice.bin[3495]: segfault at 200030000 ip 0000000200030000 sp 00007fffff42baa8 […]