Roof of Africa

Task description

They say Africa’s highest peak holds ancient secrets in its frozen glaciers. A photograph has been intercepted — but its true meaning is locked away, protected by the mountain’s most famous number.

Can you reach the summit and uncover what lies hidden?

Approach

Identify the passphrase

The description names “Africa’s highest peak” and “the mountain’s most famous number”. That is Mount Kilimanjaro; its height is 5895 m.

Check for appended data

The file ends at the JPEG EOI marker (0xFFD9) with nothing after it, so the hidden content is embedded rather than appended.

Extract with steghide

Ran steghide with the guessed passphrase in a Docker container (steghide is not available natively on Windows):

docker run --rm -e DEBIAN_FRONTEND=noninteractive -v "<files dir>":/w ubuntu:22.04 bash -c \
 'apt-get update -qq && apt-get install -y -qq steghide >/dev/null 2>&1; \
  cd /w && steghide extract -sf roof_of_africa.jpg -p 5895; cat *.txt'

Output: wrote extracted data to "roof_flag_v2.txt". The file contains the flag.