Hi Marcin
I must admit I didn’t know what bit-shifting was, as I am not a programmer. But after I looked it up for well over 30 seconds, I realised that it was completely irrelevant to anyone who is using a crack on software.
From my brief research I found out that bit-shifting operations can be used for malicious purposes, just like any programing technique though they are typically just one small part of a larger exploit or obfuscation technique. Here are some ways bit-shifting can be involved in malicious activities:
1. Code Obfuscation
Malware authors can use bit-shifting to obscure the true intent of their code, making it harder for security researchers or reverse engineers to analyze.
Example: A constant value might be split and reconstructed using shifts ((x << 8) | y) to evade signature-based detection.
2. Encoding/Encryption in Malware
Some malware uses simple bitwise operations (including shifts) as part of a weak encryption or encoding scheme to hide payloads or strings.
Example: A malware sample might XOR or shift bits in a configuration file to avoid plaintext detection.
3. Exploiting Vulnerabilities
Bit-shifting can be involved in integer overflow/underflow vulnerabilities if not properly validated.
Example: If a program shifts a value left by a large number (e.g., x << 32), it could lead to undefined behavior or unintended results, which an attacker might exploit.
4. Bypassing Security Checks
Attackers might use shifts to manipulate data in a way that bypasses security checks (e.g., converting values to evade filters).
Example: Shifting an IP address representation to bypass a blacklist check.
5. Shellcode Manipulation
Some shellcodes (low-level exploit payloads) use bit-shifting to adjust memory addresses or encode instructions dynamically.
6. Bit-Level Attacks
In cryptographic attacks, bit manipulations (including shifts) might be used in side-channel attacks or fault injection attacks to weaken security.
Defensive Considerations
While bit-shifting itself is not inherently malicious, improper use (e.g., lack of bounds checking) can introduce vulnerabilities. Security tools monitor for unusual bit manipulations in code as part of malware detection heuristics.
Bottom Line
Bit-shifting is a normal programming operation, but like any low-level technique, it can be abused as part of an attack. The maliciousness comes from the context in which it's used, not the operation itself.
Here’s a quick example of how bit-shifting can be used to
obfuscate malicious payloads or evade detection, that reconstructs a hidden string or shellcode using shifts, making static analysis harder. You will have to excuse my poor syntax, as it’s the first time I have ever done any programming or “hacking”
Example: Bit-Shifting for String Obfuscation
1. Original String (Hidden)
Suppose the malware wants to hide the string "cmd.exe" to avoid appearing in plaintext in memory or on disk.
2. Obfuscated Representation
The string is split into 2-byte chunks and stored as integers, shifted to disguise their true meaning:
c
// Obfuscated representation of "cmd.exe" (as 16-bit values shifted left by 4 bits)
unsigned int obfuscated[] = {
0x6360, // 'c' (0x63) << 4
0x6D60, // 'm' (0x6D) << 4
0x6400, // 'd' (0x64) << 4
0x2E60, // '.' (0x2E) << 4
0x6500, // 'e' (0x65) << 4
0x7860, // 'x' (0x78) << 4
0x6500 // 'e' (0x65) << 4
};
3. Malicious Decoder Routine
The malware dynamically reconstructs the string by reversing the shift:
c
#include <stdio.h>
#include <stdlib.h>
int main() {
unsigned int obfuscated[] = {0x6360, 0x6D60, 0x6400, 0x2E60, 0x6500, 0x7860, 0x6500};
char decoded[8]; // Buffer for "cmd.exe"
for (int i = 0; i < 7; i++) {
decoded
= (char)(obfuscated >> 4); // Reverse the shift
}
decoded[7] = '\0'; // Null-terminate
// Now execute the decoded command (malicious part)
system(decoded); // Runs "cmd.exe"
return 0;
}
Why This Evades Detection
- Static Analysis Evasion:
- The string "cmd.exe" never appears plainly in the binary.
- A hexdump or strings tool won’t reveal it.
- Dynamic Reconstruction:
- Only at runtime is the string reassembled, bypassing simple static checks.
- Variations for Stealth:
- Attackers might use XOR, addition, or multi-stage shifts to further obscure the payload.
Real-World Malware Techniques
- Nymaim Trojan: Used bit-shifting to hide API calls.
- APT Groups: Some advanced attackers use bit manipulation to hide C2 (Command & Control) server IPs.
- Shellcode Packers: Encode payloads with shifts to evade signature-based AV.
How to Detect Such Tricks?
- Dynamic Analysis:
- Monitor runtime behavior (e.g., strings being reconstructed in memory).
- Entropy Analysis:
- High entropy in data sections may indicate obfuscation.
- Deobfuscation Tools:
- IDA Pro, Ghidra, or custom scripts can simulate bit operations.
Key Takeaway
Bit-shifting is harmless alone, but when combined with obfuscation, it becomes a tool for hiding malicious intent. Security tools focus on behavioral patterns (e.g., system() calls with reconstructed strings) rather than the shifts themselves.
Final Conclusion
Completely and utterly irrelevant to anyone using a crack on commercial software. Because: -
The commercial software is not “open source” Therefore can’t be realistically interrogated by an individual. Especially if it is few hundred megabytes.
Most cracks tend to be automatic redirectors giving the indicators in the software the false impression that it has been registered. Very often just a small program combined to alter a serial number to the desired one. Originally taken from registered software.
Every single anti-virus software has the signatures for the cracks to software. This seems to be the most updated thing in “Anti-virus” software. So if one uses antivirus software it tends to be time consuming stopping it removing cracks and deactivating software.
Most software and crack have been downloaded thousands of times. Especially older versions. People leave feedback. One just checks the feedback.
The reason I laughed.
