Qualifier Challenge - KPRCA_00041

Original Versions

Known Vulnerabilities

  • CWE-121 - Stack-based Buffer Overflow
  • CWEs are listed as indicated by the challenge author.


  • CodeJitsu: 1.42
  • ForAllSecure: 0.64
  • Disekt: 0.6
  • TECHx: 0.16
  • CSDS: 0.16
  • Shellphish: 0.0
  • FuzzBOMB: 0.0
  • TrailofBits: 0.0
  • DeepRed: 0.0
  • The maximum score for each challenge in CQE is 4, following the CQE Scoring Document.

Passed consensus evaluation

  • CodeJitsu - CB1
  • CSDS - CB1
  • DeepRed - CB1
  • Disekt - CB1
  • ForAllSecure - CB1
  • FuzzBOMB - CB1
  • Shellphish - CB1
  • TECHx - CB1
  • TrailofBits - CB1

Proved a POV in reference challenge

Defense against reference POVs

  • CodeJitsu: 100.0% - CB1
  • Disekt: 100.0% - CB1
  • ForAllSecure: 100.0% - CB1
  • TECHx: 100.0% - CB1
  • CSDS: 100.0% - CB1
  • TrailofBits: 100.0% - CB1

No submission

  • Eighth Place Team
  • Eleventh Place Team
  • Fifth Place Team - Finalist
  • First Place Team - Finalist
  • Fourth Place Team - Finalist
  • Ninth Place Team
  • Second Place Team - Finalist
  • Seventh Place Team - Finalist
  • Sixth Place Team - Finalist
  • Tenth Place Team
  • Third Place Team - Finalist
  • Thirteenth Place Team
  • Twelfth Place Team

All Submissions

DARPA performer group

Kaprica Security (KPRCA)


Differ is an application that allows a user to look at two files and determine how they... differ. It was built to be "Slow" by making the diff analysis N^2.

Feature List

The service allows a user to upload two "Simple" files, or SFILEs. The file header is pretty simple. It has a magic value of "SFP", a few bytes to spcecify the file type (binary or asci), the name of the file (up to 15 characters) and finally the size of file data.

The user can compare the file, ignore whitespaces or treat a file as text regardless of whether it's specified as binary or ascii.

The program pre processes the entire list, and tries to help the comparison code by creating two hashes for each line as well as a version of the line that has no whitespaces (' ', '\t', '\r'). The program then painfully compares each file line by line and tries to find a best fit for changes. The goal for the "best" fit is to try to prioritize larger groupings of matched text. Because everything is using trees, instead of graphs, it's a weak fitting but good enough.

The final ouptut is a list of lines that differ from one another, as well as the text that has been added, removed, or changed.


The vulnerability is based on an "easter egg" embedded in the program. If a user has two files that are identical on every line except the 1^2, 2^2, 3^2......18^2 line, the program outputs an additional output of ":D="

However. The easter egg does an unsafe strcpy, and potentially allows a user to overflow onto the stack. From here it would be possible to take advantage of the system by overwriting stack variables.

Generic class of vulnerability

Stack Buffer Overflow

CWE classification

Stack-based Buffer Overflow (CWE-121)


This service is focused on testing code coverage of input based attacks. The easter egg is slightly contrived, but the hope is that by forcing a file of at least 961 lines, and an input of at least 4096+ bytes on the 961 (vulnerable) line, the goal is to push how effective a competitors's genetic algorithms/code coverage analysis/input generation algorithms/etc characteristics are.

Curated by Lunge Technology, LLC. Questions or comments? Send us email