Exploit Symantec AntiVirus - Heap Overflow Modifying MIME Messages

Exploiter

Хакер
34,644
0
18 Дек 2022
EDB-ID
40034
Проверка EDB
  1. Пройдено
Автор
GOOGLE SECURITY RESEARCH
Тип уязвимости
DOS
Платформа
MULTIPLE
CVE
cve-2016-3644
Дата публикации
2016-06-29
Symantec AntiVirus - Heap Overflow Modifying MIME Messages
Код:
Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=818

Symantec attempts to clean or remove components from archives or other multipart containers that they detect as malicious. The code that they use to remove components from MIME encoded messages in CMIMEParser::UpdateHeader() assumes that filenames cannot be longer than 77 characters.

This assumption is obviously incorrect, names can be any length, resulting in a very clean heap overflow.

The heap overflow occurs because Symantec does the cleaning in multiple stages, first changing the Content-Type to "text/plain", then changing the filename to "DELETED.TXT". The problem is that during the first stage of this process, they maintain the existing name but use a buffer prepared for the final name.

Something like:

char *buf = malloc(strlen(NewContentType) + strlen(LengthOfNewEncodedFilename) + 100)

// First change the content-type
strcpy(buf, "Content-Type: ");
strcpy(buf, NewContentType;
strcpy(buf, "; name=\"");
strcpy(buf, OldFileName);

...
UpdateName(buf, NewFileName);
...

This obviously won't work, because it doesn't verify that the old name will fit. I've attached an example MIME message that triggers this code in Symantec Scan Engine.


Proof of Concept:
https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/40034.zip
 
Источник
www.exploit-db.com

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