| タイトル | uftpd 2.6-2.10 Buffer Overflow |
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| 説明 | # Buffer Overflow
## Description
There is a buffer overflow vulnerability in `handle_PORT` in `ftpcmd.c` that is caused by a buffer that is 16 bytes large being filled via `sprintf` with user input based on the format specifier string `%d.%d.%d.%d`. The 16 byte size is correct for valid IPv4 addresses (`len('x.x.x.x') == 16`), but the format specifier `%d` allows more than 3 digits.
## Reproduction Steps
To reproduce this vulnerability, connect via `netcat <ip> <port>` and write to the FTP server socket the following and observe the child process spawned for the connection SIGABRT:
```
PORT 13371337,12341234,12345678,10102929,1,2
```
## Mitigation
Use `snprintf` and use the size of the buffer as the size input. Currently, it uses `inet_aton` to validate the IPv4 address, so if the user inputs an invalid address, it will be caught at that line anyway. |
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| ソース | ⚠️ https://aaronesau.com/blog/posts/6 |
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| ユーザー | arinerron (UID 4337) |
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| 送信 | 2019年08月31日 20:37 (7 年 ago) |
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| モデレーション | 2019年09月03日 07:11 (2 days later) |
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| ステータス | 承諾済み |
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| VulDBエントリ | 141192 [uftpd 2.6-2.10 ftpcmd.c handle_PORT メモリ破損] |
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| ポイント | 20 |
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