7Rocky's Blog. Cybersecurity and Maths

CTF categories

Highlighted writeups

CTF

TrapTrack

Insecure Deserialization in pickle. SSRF in Redis

CTF

Go Sweep

m0leCon CTF 2025 Teaser. Go binary. PRNG. Time-based seed. Threads

CTF

Alien Saboteaur

Virtual machine. Custom opcode instructions. sys_ptrace. XOR cipher

CTF

SecretRezipe

ZIP compression. BREACH / CRIME attacks. Known plain text attack

CTF

baby-talk

DiceCTF 2024 Quals. 64-bit binary. Heap exploitation. House of Einherjar. Overlapping chunks. Tcache poisoning

CTF

Robot Factory

64-bit binary. Buffer Overflow. Threads. Canary bypass. ret2libc

CTF

quick maffs

RSA. Low Exponent and Related Messages attack. Groebner basis. Brute force

CTF

Lost Modulus Again

RSA. Greatest Common Divisor. Franklin-Reiter related-message attack. Coppersmith’s short-pad attack

CTF

BinCrypt Breaker

Reversing encryption algorithm. XOR cipher

CTF

Recent HTB

HTB

Hack The Box. Linux. Easy machine. This machine has an outdated version of Camaleon CMS that is vulnerable to Local File Read. With this vulnerability we can read the private SSH key of a user, crack the passphrase and access the machine. Then, this user has sudo permissions to run command facter as root, which can be used to escalate privileges using a Ruby script

HTB

Interpreter

Hack The Box. Linux. Medium machine. This machine has a Mirth Connect instance that is vulnerable to Unauthenticated Remote Code Execution. After getting a reverse shell, we can find a database credentials and a hashed password inside. We must analyze how the hash is generated in order to crack it. Once we have the password, we can access via SSH and find out an internal webserver running as root that has a code injection vullnerability in Python due to eval and f-strings, which allows us to escalate to root

HTB

Eighteen

Hack The Box. Windows. Easy machine. In this assumed-breach machine we have credentials for an exposed MSSQL service where we can impersonate another user and find a hashed password for the website hosted by the machine. This hash can be cracked to find a password. After enumerating users by brute forcing RIDs in MSSQL, we find that it is reused by a domain user and we get access via WinRM. There is a bad ACL configured to group IT and we can use BadSuccessor to escalate privileges, after configuring a SOCKS proxy to access required AD services

HTB

Dog

Hack The Box. Linux. Easy machine. This machine hosts a CMS that exposes a Git repository. Once we dump the repository, we can find a username and a database password that can be reused to log in as administrator of the CMS. Here, we can install a new module to execute a PHP web shell and get a reverse shell on the machine. Although there are hashed passwords on the database, the same password can be reused for a system user. Finally, we are allowed to run bee as root using sudo, which will let us escalate privileges by running arbitrary PHP code

HTB

Titanic

Hack The Box. Linux. Easy machine. This machine has a Local File Read vulnerability where we can read sensitive files. There is a Gitea instance with some repositories and a Docker configuration that shows how Gitea files are shared in a volume mount. So, we can find hashed passwords on the Gitea SQLite database and crack them. With this, we gain access via SSH reusing credentials. After that, we find a script running as root using a vulnerable version of ImageMagick where we can perform a library hijacking to get arbitrary code execution, as root

More HTB

Recent IMC

IMC

IMC 2021, Problem 1

Let

be a real

matrix such that

Prove that there is a unique real matrix that satisfies the equation
Express in terms of .

IMC

IMC 2020, Problem 5

Find all twice continuously differentiable functions

satisfying

for all

IMC

IMC 2020, Problem 2

Let

and

real matrices such that

where

is the

identity matrix. Prove that

IMC

IMC 2020, Problem 1

Let

be a positive integer. Compute the number of words

(finite sequences of letters) that satisfy the following three properties:

consists of letters, all of them are from the alphabet .
contains an even number of letters .
contains an even number of letters .

(For example, for

, there are 6 such words:

and

)

More IMC

7Rocky