Qualifier Challenge - NRFIN_00026

Original Versions

Known Vulnerabilities

  • CWE-121 - Stack-based Buffer Overflow
  • CWE-131 - Incorrect Calculation of Buffer Size
  • CWEs are listed as indicated by the challenge author.


  • CSDS: 1.78
  • Shellphish: 1.0
  • TrailofBits: 0.76
  • Disekt: 0.0
  • The maximum score for each challenge in CQE is 4, following the CQE Scoring Document.

Passed consensus evaluation

  • CSDS - CB1
  • TrailofBits - CB1

Proved a POV in reference challenge

Defense against reference POVs

  • CSDS: 100.0% - CB1
  • TrailofBits: 98.9% - CB1
  • Shellphish: 0.6% - 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

Author Information

"Ben Schmidt" info@narfindustries.com

DARPA performer group

Narf Industries (NRFIN)


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A simple stack buffer overflow vulnerability exists inside customprotos.c in dissector function process_trolololo due to incorrect calculation of maximum input buffer size. By providing a bsize value greater than 12 but less than 48, it is possible to overflow the local stack buffer "buf". To complicate exploitation, this function is protected by a custom stack canary function. Competitor's must be able to defeat this in addition to overflowing the buffer to prove vulnerability. In practice, this vulnerability is very similar to CVE-2013-5720.

Additionally, there are 180 other autogenerated vulnerabilities that allow for access outside the bounds of an array leading to the use of an invalid function pointer. These serve to test CRS ability to detect and patch the same vulnerability spread across a CB, as well as the ability to seperate casual analysis of the binary (which will find this) to more in-depth analysis.

Generic class of vulnerability

Buffer overflow Improper bounds checking

CWE classification

CWE-131: Incorrect Calculation of Buffer Size CWE-121: Stack-based buffer overflow


  • Competitors must correctly follow a large number of calls through function pointers in their analysis.
  • Competitors must deal with a large (~12MB) CB and discover a vulnerability in one of many, very similar, functions.
  • Competitors must utilize control over a local variable to avoid triggering stack cookie checks but still causing a crash.
  • Competitors must find and mitigate a large number of potential vulnerabilities.

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