Lets connect to the challenge instance
You can see from the above screenshot that we can't use the normal linux commands here.
To solve this chall we'll make use of wildcards
Wildcards are characters used in shell commands to represent one or more other characters. They're commonly used in file management commands to specify patterns of filenames that you want to match. Here are some common wildcards:
* (asterisk): Matches any sequence of characters, including none.
? (question mark): Matches any single character.
[ ] (square brackets): Matches any one character within the specified range or set.
Here's how they work in practice:
*: Matches zero or more characters.
Example: *.txt matches any file ending in .txt.
?: Matches exactly one character.
Example: file?.txt matches file1.txt, fileA.txt, but not file12.txt.
[ ]: Matches any one character within the specified range or set.
Example: [123].txt matches 1.txt, 2.txt, or 3.txt.
Lets try to cause an error
You can see that theere's a bash script in that directory but then we don't know the directory we are sitted at
To try to read a file in this directory we can try using the wildcards we can just use the wildcard . ???? where ??? represents the length of the file we want to read and ```. when used as a standalone character refers to the current working directory
We were able to read the lol.txt file
Lets make an assumption here, we'll assume that the flag is in the flag.txt file, so to read this we can use the wildcard . ????????
We got our flag
FLAG:-ACTF{Th4t_w4s_5impl3_wasnt_it?}