CVE-2020-8908 — Temp directory permission issue in Guava

Affected: Google LLC Guava

A temp directory creation vulnerability exists in all versions of Guava, allowing an attacker with access to the machine to potentially access data in a temporary directory created by the Guava API com.google.common.io.Files.createTempDir(). By default, on unix-like systems, the created directory is world-readable (readable by an attacker with access to the system). The method in question has been marked @Deprecated in versions 30.0 and later and should not be used. For Android developers, we recommend choosing a temporary directory API provided by Android, such as context.getCacheDir(). For other Java developers, we recommend migrating to the Java 7 API java.nio.file.Files.createTempDirectory() which explicitly configures permissions of 700, or configuring the Java runtime's java.io.tmpdir system property to point to a location whose permissions are appropriately configured.

GHSA-38f8-5428-x5cv — Netty vulnerable to HTTP Request Smuggling due to malformed Transfer-Encoding

Affected: Maven: io.netty:netty-codec-http

### Summary Netty incorrectly parses malformed Transfer-Encoding, enabling request smuggling attacks.

### Details Netty incorrectly marks a request as chunked when malformed "Transfer-Encoding: chunked, identity" is present. According to RFC https://datatracker.ietf.org/doc/html/rfc9112#name-message-body-length

" If a Transfer-Encoding header field is present in a request and the chunked transfer coding is not the final encoding, the message body length cannot be determined reliably; the server MUST respond with the 400 (Bad Request) status code and then close the connection. "

A possible scenario is when Netty is behind a proxy that doesn't reject requests with "Transfer-Encoding: chunked, identity", but prefers "Content-Length" and forwards the content to Netty.

### PoC The test below shows Netty successfully parsing the second request, demonstrating how an attacker can smuggle a second request inside a request body.

```java @Test public void test() { String requestStr = "POST / HTTP/1.1\r\n" + "Host: localhost\r\n" + "Transfer-Encoding: chunked, identity\r\n" + "Content-Length: 48\r\n" + "\r\n" + "0\r\n" + "\r\n" + "GET /smuggled HTTP/1.1\r\n" + "Host: localhost\r\n" + "\r\n";

EmbeddedChannel channel = new EmbeddedChannel(new HttpRequestDecoder()); assertTrue(channel.writeInbound(Unpooled.copied…

Most recent entries from all

CVE-2020-8908 — Temp directory permission issue in Guava

GHSA-38f8-5428-x5cv — Netty vulnerable to HTTP Request Smuggling due to malformed Transfer-Encoding