【逆向分析】BUUCTF 逆向题目 [BJDCTF2020]JustRE

https://buuoj.cn/challenges#[BJDCTF2020]JustRE

https://files.buuoj.cn/files/b02a88388c5a572e39c2d40b8e9136fc/attachment.exe

信息:     文件名: H:/第七届“强网杯”全国网络安全挑战赛/BUUCTF/[BJDCTF2020]JustRE/attachment.exe    大小: 40855(39.90 KiB)    操作系统: Windows(95)    架构: I386    模式: 32 位    类型: GUI    字节序: LE

.data:00407030 aBjdDD2069a4579 db ' BJD{%d%d2069a45792d233ac}',0

sprintf(String, " BJD{%d%d2069a45792d233ac}", 19999, 0);

int sprintf( char *buffer, const char *format, [ argument] … );

#include <stdio.h>
int main() {    // Use a constant for the buffer size    const int bufferSize = 0x100;    char String[bufferSize];
    // Use snprintf to avoid potential buffer overflow    int writtenChars = snprintf(String, bufferSize, "BJD{%d%d2069a45792d233ac}", 19999, 0);
    // Check for snprintf failure    if (writtenChars < 0 || writtenChars >= bufferSize) {        fprintf(stderr, "Error: Buffer overflow or snprintf failuren");        return 1;    }
    // Use fputs instead of puts for better control (no automatic newline)    if (fputs(String, stdout) == EOF) {        fprintf(stderr, "Error: fputs failedn");        return 1;    }
    return 0;}

flag{1999902069a45792d233ac}