A flaw was found Go's net/http package. Servers using ReverseProxy from net/http in the Go standard library are vulnerable to a data race that results in a denial of service. The highest threat from this vulnerability is to system availability.

A flaw was found in the Go standard library packages before upstream versions 1.15 and 1.14.8. Both the net/http/cgi and net/http/fcgi packages use a default Content-Type response header value of "text/html", rather than "text/plain". This flaw allows an attacker to exploit this issue in applications using these packages by uploading crafted files, allowing a Cross-site Scripting attack (XSS). The highest threat from this vulnerability is to confidentiality and integrity.

An attacker can cause excessive memory growth in a Go server accepting HTTP/2 requests. HTTP/2 server connections contain a cache of HTTP header keys sent by the client. While the total number of entries in this cache is capped, an attacker sending very large keys can cause the server to allocate approximately 64 MiB per open connection.

A flaw detected in golang: crypto/elliptic, in which P-224 keys as generated can return incorrect inputs, reducing the strength of the cryptography. The highest threat from this vulnerability is confidentiality and integrity.

Summary

Terrapin is a prefix truncation attack targeting the SSH protocol. More precisely, Terrapin breaks the integrity of SSH's secure channel. By carefully adjusting the sequence numbers during the handshake, an attacker can remove an arbitrary amount of messages sent by the client or server at the beginning of the secure channel without the client or server noticing it.

Mitigations

To mitigate this protocol vulnerability, OpenSSH suggested a so-called "strict kex" which alters the SSH handshake to ensure a Man-in-the-Middle attacker cannot introduce unauthenticated messages as well as convey sequence number manipulation across handshakes.

Warning: To take effect, both the client and server must support this countermeasure.

As a stop-gap measure, peers may also (temporarily) disable the affected algorithms and use unaffected alternatives like AES-GCM instead until patches are available.

Details

The SSH specifications of ChaCha20-Poly1305 (chacha20-poly1305@openssh.com) and Encrypt-then-MAC (-etm@openssh.com MACs) are vulnerable against an arbitrary prefix truncation attack (a.k.a. Terrapin attack). This allows for an extension negotiation downgrade by stripping the SSHMSGEXTINFO sent after the first message after SSHMSGNEWKEYS, downgrading security, and disabling attack countermeasures in some versions of OpenSSH. When targeting Encrypt-then-MAC, this attack requires the use of a CBC cipher to be practically exploitable due to the internal workings of the cipher mode. Additionally, this novel attack technique can be used to exploit previously unexploitable implementation flaws in a Man-in-the-Middle scenario.

The attack works by an attacker injecting an arbitrary number of SSHMSGIGNORE messages during the initial key exchange and consequently removing the same number of messages just after the initial key exchange has concluded. This is possible due to missing authentication of the excess SSHMSGIGNORE messages and the fact that the implicit sequence numbers used within the SSH protocol are only checked after the initial key exchange.

In the case of ChaCha20-Poly1305, the attack is guaranteed to work on every connection as this cipher does not maintain an internal state other than the message's sequence number. In the case of Encrypt-Then-MAC, practical exploitation requires the use of a CBC cipher; while theoretical integrity is broken for all ciphers when using this mode, message processing will fail at the application layer for CTR and stream ciphers.

For more details see https://terrapin-attack.com.

Impact

This attack targets the specification of ChaCha20-Poly1305 (chacha20-poly1305@openssh.com) and Encrypt-then-MAC (-etm@openssh.com), which are widely adopted by well-known SSH implementations and can be considered de-facto standard. These algorithms can be practically exploited; however, in the case of Encrypt-Then-MAC, we additionally require the use of a CBC cipher. As a consequence, this attack works against all well-behaving SSH implementations supporting either of those algorithms and can be used to downgrade (but not fully strip) connection security in case SSH extension negotiation (RFC8308) is supported. The attack may also enable attackers to exploit certain implementation flaws in a man-in-the-middle (MitM) scenario.

In ISC BIND9 versions BIND 9.11.14 -> 9.11.19, BIND 9.14.9 -> 9.14.12, BIND 9.16.0 -> 9.16.3, BIND Supported Preview Edition 9.11.14-S1 -> 9.11.19-S1: Unless a nameserver is providing authoritative service for one or more zones and at least one zone contains an empty non-terminal entry containing an asterisk ("") character, this defect cannot be encountered. A would-be attacker who is allowed to change zone content could theoretically introduce such a record in order to exploit this condition to cause denial of service, though we consider the use of this vector unlikely because any such attack would require a significant privilege level and be easily traceable.

A flaw was found in bind. When flooding the target resolver with special queries, an attacker can significantly impair the resolver's performance, effectively denying legitimate clients access to the DNS resolution service.

A flaw was found in the System Security Services Daemon (SSSD). The pampasskeychildreaddata() function within the PAM passkey responder fails to properly handle raw bytes received from a pipe. Because the data is treated as a NUL-terminated C string without explicit termination, it results in an out-of-bounds read when processed by functions like snprintf(). A local attacker could potentially trigger this vulnerability by initiating a crafted passkey authentication request, causing the SSSD PAM responder to crash, resulting in a local Denial of Service (DoS).

A flaw was found in SSSD. The sssnssprotocolparseaddr() function in the NSS responder (src/responder/nss/nssprotocol.c) extracts a 32-bit addrlen value from the client request but only validates that the body is at least 8 bytes, without checking that addrlen fits within the remaining packet body. This unvalidated length is passed through to tallocmemdup() in cachereqdatacreate(), which copies addrlen bytes from the small request buffer, causing a heap-buffer-overflow read. A local attacker can trigger this by connecting to the world-writable NSS responder socket (/var/lib/sss/pipes/nss) and sending a SSSNSSGETHOSTBYADDR (0x0053) request with a large addrlen value and a valid address family payload so that inetntop() succeeds. Successful exploitation crashes the sssdnss responder, causing a denial of service for NSS name resolution. Reported via PSIRTSUPT-20553 by BreachX Zero Day Labs.

A flaw was found in sssd. When authenticating with a YubiKey, the SSSD PAM responder can crash due to a use-after-free vulnerability, where a memory pointer is incorrectly handled. A local attacker could exploit this flaw by manipulating smartcard or YubiKey contents, leading to a denial of service that disrupts authentication. This vulnerability also presents a potential for privilege escalation, although it is difficult to exploit.

A content injection vulnerability was found in the ABRT post-create event handler scripts in libreport. The event script queries the systemd journal for log entries matching the crashed process and writes the results to files in the dump directory without sanitizing embedded control characters. A local user can inject arbitrary content into the journal output by embedding newline characters in syslog messages, controlling the content that root writes to dump directory files.

A flaw was found in the way the BMPImageReader class implementation in the ImageIO component of OpenJDK handled memory allocations when processing uncompressed BMP images. A specially-crafted BMP image with a small size could cause a Java application to allocate an excessive amount of memory and possibly terminate on out-of-memory condition.

A flaw was found in the SSL logger implementation in the JSSE component of OpenJDK. A malicious client could cause a Java application acting as TLS server to raise an unexpected exception during TLS handshake.

An unspecified vulnerability in Java SE related to the JSSE component could allow an unauthenticated attacker to obtain sensitive information resulting in a high confidentiality impact using unknown attack vectors.

It was discovered that the Kerberos protocol implementation in the Libraries component of OpenJDK did not correctly report subject principals when using Kerberos Constrained Delegation. This could lead to the use of wrong Kerberos tickets.

A flaw was found in the way the Keytool component of OpenJDK handled X.509 certificates with validity period ending too far in the future, after year 9999. When such certificates were imported into a keystore, they could cause corruption of the keystore.

A flaw was found in the way the RTFReader class implementation in the Swing component of OpenJDK handled style keyword parameters. A specially crafted Rich Text Format (RTF) file could cause a Java application using RTFReader to allocate an excessive ammount of memory and possibly terminate on out-of-memory condition.

An inifinte loop flaw was found in the HttpsServer class implementation in the JSSE component of OpenJDK. A remote attacker could possibly use this flaw to cause a Java application implementing HTTPS server functionality to loop during the TLS session closing and consume an excessive amount of CPU time.

A flaw was found in the way the RTFParser class implementation in the Swing component of OpenJDK handled memory allocations. A specially crafted Rich Text Format (RTF) file could cause a Java application using RTFParser to allocate an excessive amount of memory and possibly terminate on out-of-memory condition.

A CRLF injection flaw was found in the Lightweight HTTP Server component of OpenJDK. The HttpServer implementation did not restrict the use of CR and LF characters in values for HTTP headers, possibly allowing HTTP response splitting attacks.

A regular expression denial of service flaw was found in the Concurrency component of OpenJDK. The use of overly complex regular expressions in java.utils.Scanner could cause a high CPU usage when Scanner was used on parse certain inputs.

A flaw was found in the way the HashMap and the HashSet classes implementations in the Utility component of OpenJDK validated the load factor value during deserialization. A specially crafted serialized data stream could cause a Java application to allocate an excessive amount of memory and possibly terminate on out-of-memory condition when deserialized.

A flaw was found in the way the TLS implementation in the JSSE component of OpenJDK re-used single null TLS sessions for new TLS connections. A remote attacker could possibly use this flaw to impact availability of a Java application providing TLS server.

Impact Accepting the value of various Text options of the Datepicker widget from untrusted sources may execute untrusted code. For example, initializing the datepicker in the following way: js $( "#datepicker" ).datepicker( { showButtonPanel: true, showOn: "both", closeText: "<script>doEvilThing( 'closeText XSS' )</script>", currentText: "<script>doEvilThing( 'currentText XSS' )</script>", prevText: "<script>doEvilThing( 'prevText XSS' )</script>", nextText: "<script>doEvilThing( 'nextText XSS' )</script>", buttonText: "<script>doEvilThing( 'buttonText XSS' )</script>", appendText: "<script>doEvilThing( 'appendText XSS' )</script>", } ); will call doEvilThing with 6 different parameters coming from all Text options.

Patches The issue is fixed in jQuery UI 1.13.0. The values passed to various Text options are now always treated as pure text, not HTML.

Workarounds A workaround is to not accept the value of the Text options from untrusted sources.

For more information If you have any questions or comments about this advisory, search for a relevant issue in the jQuery UI repo. If you don't find an answer, open a new issue.

Impact Accepting the value of the of option of the .position() util from untrusted sources may execute untrusted code. For example, invoking the following code: js $( "#element" ).position( { my: "left top", at: "right bottom", of: "<img onerror='doEvilThing()' src='/404' />", collision: "none" } ); will call the doEvilThing() function.

Patches The issue is fixed in jQuery UI 1.13.0. Any string value passed to the of option is now treated as a CSS selector.

Workarounds A workaround is to not accept the value of the of option from untrusted sources.

For more information If you have any questions or comments about this advisory, search for a relevant issue in the jQuery UI repo. If you don't find an answer, open a new issue.

Impact Accepting the value of the altField option of the Datepicker widget from untrusted sources may execute untrusted code. For example, initializing the datepicker in the following way: js $( "#datepicker" ).datepicker( { altField: "<img onerror='doEvilThing()' src='/404' />", } ); will call the doEvilThing function.

Patches The issue is fixed in jQuery UI 1.13.0. Any string value passed to the altField option is now treated as a CSS selector.

Workarounds A workaround is to not accept the value of the altField option from untrusted sources.

For more information If you have any questions or comments about this advisory, search for a relevant issue in the jQuery UI repo. If you don't find an answer, open a new issue.

A cross-site scripting (XSS) vulnerability in the HTML Data Processor for CKEditor 4.0 before 4.14 allows remote attackers to inject arbitrary web script through a crafted "protected" comment (with the ckeprotected syntax).

A flaw was found in the Linux kernel. A local attacker, able to inject conntrack netlink configuration, could overflow a local buffer causing crashes or triggering the use of incorrect protocol numbers in ctnetlinkparsetuplefilter in net/netfilter/nfconntracknetlink.c. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Impact

Since Requests v2.3.0, Requests has been vulnerable to potentially leaking Proxy-Authorization headers to destination servers, specifically during redirects to an HTTPS origin. This is a product of how rebuildproxies is used to recompute and reattach the Proxy-Authorization header to requests when redirected. Note this behavior has only been observed to affect proxied requests when credentials are supplied in the URL user information component (e.g. https://username:password@proxy:8080).

Current vulnerable behavior(s):

1. HTTP → HTTPS: leak 2. HTTPS → HTTP: no leak 3. HTTPS → HTTPS: leak 4. HTTP → HTTP: no leak

For HTTP connections sent through the proxy, the proxy will identify the header in the request itself and remove it prior to forwarding to the destination server. However when sent over HTTPS, the Proxy-Authorization header must be sent in the CONNECT request as the proxy has no visibility into further tunneled requests. This results in Requests forwarding the header to the destination server unintentionally, allowing a malicious actor to potentially exfiltrate those credentials.

The reason this currently works for HTTPS connections in Requests is the Proxy-Authorization header is also handled by urllib3 with our usage of the ProxyManager in adapters.py with proxymanagerfor. This will compute the required proxy headers in proxyheaders and pass them to the Proxy Manager, avoiding attaching them directly to the Request object. This will be our preferred option going forward for default usage.

Patches Starting in Requests v2.31.0, Requests will no longer attach this header to redirects with an HTTPS destination. This should have no negative impacts on the default behavior of the library as the proxy credentials are already properly being handled by urllib3's ProxyManager.

For users with custom adapters, this may be potentially breaking if you were already working around this behavior. The previous functionality of rebuildproxies doesn't make sense in any case, so we would encourage any users impacted to migrate any handling of Proxy-Authorization directly into their custom adapter.

Workarounds For users who are not able to update Requests immediately, there is one potential workaround.

You may disable redirects by setting allowredirects to False on all calls through Requests top-level APIs. Note that if you're currently relying on redirect behaviors, you will need to capture the 3xx response codes and ensure a new request is made to the redirect destination. import requests r = requests.get('http://github.com/', allowredirects=False)

Credits

This vulnerability was discovered and disclosed by the following individuals.

Dennis Brinkrolf, Haxolot (https://haxolot.com/) Tobias Funke, (tobiasfunke93@gmail.com)

A server side request forgery (SSRF) flaw was found in Kubernetes. The kube-controller-manager allows authorized users with the ability to create StorageClasses or certain Volume types to leak up to 500 bytes of arbitrary information from the master's host network. This can include secrets from the kube-apiserver through the unauthenticated localhost port (if enabled).