In Jenkins 2.579 and earlier, LTS 2.568.2 and earlier, transient fields cannot be excluded from deserialization, allowing attackers able to submit configuration updates to specify the values of transient fields that will be deserialized, the impact depending on how those fields are used.

In Jenkins 2.579 and earlier, LTS 2.568.2 and earlier, objects of types marked as storing their configuration in independent top-level configuration files in Jenkins (such as the global configuration and jobs) can appear as nested field values in user-submitted config.xml documents and subsequently handle HTTP requests via Stapler, resulting in remote code execution.

In Jenkins 2.579 and earlier, LTS 2.568.2 and earlier, the system log viewer does not escape log record metadata (source, level, and timestamp) resulting in a stored cross-site scripting (XSS) vulnerability exploitable by attackers in control of agent processes.

In Jenkins 2.579 and earlier, LTS 2.568.2 and earlier, Jenkins does not rotate the session when a user is authenticated via the "remember me" cookie, allowing attackers able to serve content on the same site as Jenkins to set a known session cookie in the victim's browser, which after the victim authenticates via the "remember me" cookie, grants the attacker access to Jenkins as that user.

Jenkins 2.554 and earlier, LTS 2.541.2 and earlier does not safely handle symbolic links during the extraction of .tar and .tar.gz archives, allowing crafted archives to write files to arbitrary locations on the filesystem, restricted only by file system access permissions of the user running Jenkins. This can be exploited to deploy malicious scripts or plugins on the controller by attackers with Item/Configure permission, or able to control agent processes.

In Jenkins 2.567 and earlier, LTS 2.555.2 and earlier, it is possible for attackers to have Jenkins deserialize arbitrary types defined in Jenkins core or plugins from an attacker-controlled config.xml submission in a way that allows them to handle HTTP requests afterwards. This can be used to impersonate any user and send HTTP requests on their behalf, up to and including use of the Script Console to run arbitrary code, or to read arbitrary files from the Jenkins controller.

Jenkins 2.567 and earlier, LTS 2.555.2 and earlier improperly determines that a redirect URL after login is legitimately pointing to Jenkins when it contains tab or newline characters between //, allowing attackers to perform phishing attacks.

Jenkins 2.575 and earlier, LTS 2.568.1 and earlier handles case-insensitivity in user names and group names inconsistently, allowing attackers able to create new users or groups with names that case-insensitively match other characters to impersonate other users or be granted their permissions in some circumstances.

Jenkins Script Security Plugin 1402.v94c9ce464861 and earlier does not reject Groovy AST transformation annotations carrying an extensions member, allowing attackers able to run sandboxed Groovy scripts to execute code outside the sandbox if a suitable script is present on the classpath of the component that evaluates the script.

In Stapler 2107.v8dfcbe8ed317 and earlier, except 2088.2093.vd7c3e58008a6, included in Jenkins 2.579 and earlier, LTS 2.568.2 and earlier, Stapler does not restrict the types of objects that can be instantiated via form data binding to those compatible with the expected field type, allowing attackers with Overall/Read permission to instantiate types related to configuration for which that field type was not intended.

Jenkins Performance Plugin 1015.v09ca52b3370e and earlier does not restrict the classes that can be instantiated when deserializing cached performance reports stored in the build directory on the Jenkins controller, allowing attackers with Item/Configure permission to execute arbitrary code on the Jenkins controller.

Jenkins File Parameter Plugin 425.v3fa801681b5e and earlier allows writing files to arbitrary locations on the Jenkins controller file system through Stapler data binding, which can lead to remote code execution.

Jenkins SonarQube Scanner Plugin 2.18.3 and earlier does not limit URL schemes for the dashboard links it creates based on SonarQube scanner results, allowing the javascript: scheme, resulting in a stored cross-site scripting (XSS) vulnerability exploitable by attackers with Item/Configure permission.

Jenkins ThinBackup Plugin 2.1.4 and earlier allows overwriting the plugin's backup configuration through Stapler data binding, allowing attackers to redirect backup writes to an attacker-specified directory and to include arbitrary files from the Jenkins controller file system in backups.

A path traversal vulnerability in Jenkins Allure Plugin 2.35.2 and earlier allows attackers with Item/Read permission on jobs that publish Allure report results to read arbitrary files on the Jenkins controller's file system.

Jenkins SAML Plugin 4.618.v441a27fa46d2 and earlier allows overwriting the SAML identity provider metadata file through Stapler data binding, allowing attackers to replace it with attacker-controlled content and authenticate as any user.

Jenkins Multijob Plugin 669.v9d96ad9c71b0 and earlier provides Groovy scripting features that do not integrate with Script Security Plugin, allowing attackers with Item/Create or Item/Configure permission to execute arbitrary code in the context of the Jenkins controller JVM.

Jenkins Script Security Plugin 1402.v94c9ce464861 and earlier does not reject Groovy AST transformation annotations carrying an extensions member, allowing attackers able to run sandboxed Groovy scripts to execute code outside the sandbox if a suitable script is present on the classpath of the component that evaluates the script.

In Jenkins 2.567 and earlier, LTS 2.555.2 and earlier, it is possible for attackers to have Jenkins deserialize arbitrary types defined in Jenkins core or plugins from an attacker-controlled config.xml submission in a way that allows them to handle HTTP requests afterwards. This can be used to impersonate any user and send HTTP requests on their behalf, up to and including use of the Script Console to run arbitrary code, or to read arbitrary files from the Jenkins controller.

Jenkins 2.567 and earlier, LTS 2.555.2 and earlier improperly determines that a redirect URL after login is legitimately pointing to Jenkins when it contains tab or newline characters between //, allowing attackers to perform phishing attacks.

Rejected reason: This CVE ID has been rejected or withdrawn by its CVE Numbering Authority.

HTTP/2 Rapid reset attack The HTTP/2 protocol allows clients to indicate to the server that a previous stream should be canceled by sending a RSTSTREAM frame. The protocol does not require the client and server to coordinate the cancellation in any way, the client may do it unilaterally. The client may also assume that the cancellation will take effect immediately when the server receives the RSTSTREAM frame, before any other data from that TCP connection is processed.

Abuse of this feature is called a Rapid Reset attack because it relies on the ability for an endpoint to send a RSTSTREAM frame immediately after sending a request frame, which makes the other endpoint start working and then rapidly resets the request. The request is canceled, but leaves the HTTP/2 connection open.

The HTTP/2 Rapid Reset attack built on this capability is simple: The client opens a large number of streams at once as in the standard HTTP/2 attack, but rather than waiting for a response to each request stream from the server or proxy, the client cancels each request immediately.

The ability to reset streams immediately allows each connection to have an indefinite number of requests in flight. By explicitly canceling the requests, the attacker never exceeds the limit on the number of concurrent open streams. The number of in-flight requests is no longer dependent on the round-trip time (RTT), but only on the available network bandwidth.

In a typical HTTP/2 server implementation, the server will still have to do significant amounts of work for canceled requests, such as allocating new stream data structures, parsing the query and doing header decompression, and mapping the URL to a resource. For reverse proxy implementations, the request may be proxied to the backend server before the RSTSTREAM frame is processed. The client on the other hand paid almost no costs for sending the requests. This creates an exploitable cost asymmetry between the server and the client.

Multiple software artifacts implementing HTTP/2 are affected. This advisory was originally ingested from the swift-nio-http2 repo advisory and their original conent follows.

swift-nio-http2 specific advisory swift-nio-http2 is vulnerable to a denial-of-service vulnerability in which a malicious client can create and then reset a large number of HTTP/2 streams in a short period of time. This causes swift-nio-http2 to commit to a large amount of expensive work which it then throws away, including creating entirely new Channels to serve the traffic. This can easily overwhelm an EventLoop and prevent it from making forward progress.

swift-nio-http2 1.28 contains a remediation for this issue that applies reset counter using a sliding window. This constrains the number of stream resets that may occur in a given window of time. Clients violating this limit will have their connections torn down. This allows clients to continue to cancel streams for legitimate reasons, while constraining malicious actors.

A Cross-site request forgery (CSRF) vulnerability was found in a Jenkins plugin. This issue may allow an authenticated attacker to access Jenkins builds, bypassing CSRF protections.

Jenkins 2.299 and earlier, LTS 2.289.1 and earlier does not invalidate the previous session on login.

A flaw was found in jenkins. Users with Agent/Configure permissions can choose agent names that cause an override to the global config.xml file. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

A flaw was found in jenkins. An attacker with permission to create or configure various objects to inject crafted content into Old Data Monitor can cause the instantiation of potentially unsafe objects once discarded by an administrator. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

An integer overflow in MetaDataBuilder.checkSize allows for HTTP/2 HPACK header values to exceed their size limit.

In MetaDataBuilder.java, the following code determines if a header name or value exceeds the size limit, and throws an exception if the limit is exceeded:

java 291 public void checkSize(int length, boolean huffman) throws SessionException 292 { 293 // Apply a huffman fudge factor 294 if (huffman) 295 length = (length 4) / 3; 296 if ((size + length) > maxSize) 297 throw new HpackException.SessionException("Header too large %d > %d", size + length, maxSize); 298 }

However, when length is very large and huffman is true, the multiplication by 4 in line 295 will overflow, and length will become negative. (size+length) will now be negative, and the check on line 296 will not be triggered.

Furthermore, MetaDataBuilder.checkSize allows for user-entered HPACK header value sizes to be negative, potentially leading to a very large buffer allocation later on when the user-entered size is multiplied by 2.

In MetaDataBuilder.java, the following code determines if a header name or value exceeds the size limit, and throws an exception if the limit is exceeded:

java public void checkSize(int length, boolean huffman) throws SessionException { // Apply a huffman fudge factor if (huffman) length = (length 4) / 3; if ((size + length) > maxSize) throw new HpackException.SessionException("Header too large %d > %d", size + length, maxSize); }

However, no exception is thrown in the case of a negative size. Later, in Huffman.decode, the user-entered length is multiplied by 2 before allocating a buffer:

java public static String decode(ByteBuffer buffer, int length) throws HpackException.CompressionException { Utf8StringBuilder utf8 = new Utf8StringBuilder(length 2); // ...

This means that if a user provides a negative length value (or, more precisely, a length value which, when multiplied by the 4/3 fudge factor, is negative), and this length value is a very large positive number when multiplied by 2, then the user can cause a very large buffer to be allocated on the server.

Exploit Scenario 1 An attacker repeatedly sends HTTP messages with the HPACK header 0x00ffffffffff02. Each time this header is decoded: + HpackDecode.decode will determine that a Huffman-coded value of length 805306494 needs to be decoded. + MetaDataBuilder.checkSize will approve this length. + Huffman.decode will allocate a 1.6 GB string array. + Huffman.decode will have a buffer overflow error, and the array will be deallocated the next time garbage collection happens. (Note: this can be delayed by appending valid huffman-coded characters to the end of the header.)

Depending on the timing of garbage collection, the number of threads, and the amount of memory available on the server, this may cause the server to run out of memory.

Exploit Scenario 2 An attacker repeatedly sends HTTP messages with the HPACK header 0x00ff8080ffff0b. Each time this header is decoded: + HpackDecode.decode will determine that a Huffman-coded value of length -1073758081 needs to be decoded + MetaDataBuilder.checkSize will approve this length + The number will be multiplied by 2 to get 2147451134, and Huffman.decode will allocate a 2.1 GB string array + Huffman.decode will have a buffer overflow error, and the array will be deallocated the next time garbage collection happens (Note that this deallocation can be delayed by adding valid Huffman-coded characters to the end of the header)

Depending on the timing of garbage collection, the number of threads, and the amount of memory available on the server, this may cause the server to run out of memory.

Impact Users of HTTP/2 can be impacted by a remote denial of service attack.

Patches Fixed in Jetty 10.0.16 and Jetty 11.0.16 Fixed in Jetty 9.4.53 Jetty 12.x is unaffected.

Workarounds No workarounds possible, only patched versions of Jetty.

References https://github.com/eclipse/jetty.project/pull/9634

XStream is an open source java library to serialize objects to XML and back again. Versions prior to 1.4.19 may allow a remote attacker to allocate 100% CPU time on the target system depending on CPU type or parallel execution of such a payload resulting in a denial of service only by manipulating the processed input stream. XStream 1.4.19 monitors and accumulates the time it takes to add elements to collections and throws an exception if a set threshold is exceeded. Users are advised to upgrade as soon as possible. Users unable to upgrade may set the NOREFERENCE mode to prevent recursion. See GHSA-rmr5-cpv2-vgjf for further details on a workaround if an upgrade is not possible.

Description Invalid HTTP/2 requests (for example, invalid URIs) are incorrectly handled by writing a blocking error response directly from the selector thread. If the client manages to exhaust the HTTP/2 flow control window, or TCP congest the connection, the selector thread will be blocked trying to write the error response. If this is repeated for all the selector threads, the server becomes unresponsive, causing the denial of service.

Impact A malicious client may render the server unresponsive.

Patches The fix is available in Jetty versions 9.4.47. 10.0.10, 11.0.10.

Workarounds No workaround available within Jetty itself. One possible workaround is to filter the requests before sending them to Jetty (for example in a proxy)

For more information If you have any questions or comments about this advisory: Email us at security@webtide.com.

Jenkins Script Security Plugin 1402.v94c9ce464861 and earlier does not intercept the implicit type casts applied to the elements of typed for-each loops in sandboxed Groovy scripts, allowing attackers able to provide such scripts to invoke arbitrary constructors and bypass the sandbox protection.