Certifi 2023.07.22 removes root certificates from "e-Tugra" from the root store. These are in the process of being removed from Mozilla's trust store.

e-Tugra's root certificates are being removed pursuant to an investigation prompted by reporting of security issues in their systems. Conclusions of Mozilla's investigation can be found here.

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.

A vulnerability was found in MariaDB. An OpenVAS port scan on ports 3306 and 4567 allows a malicious remote client to cause a denial of service.

A flaw has been identified in glibc. In an uncommon situation, the gaihinet function may use memory that has been freed, resulting in an application crash. This issue is only exploitable when the getaddrinfo function is called and the hosts database in /etc/nsswitch.conf is configured with SUCCESS=continue or SUCCESS=merge.

A vulnerability was found in libX11 due to a boundary condition within the XkbReadKeySyms() function. This flaw allows a local user to trigger an out-of-bounds read error and read the contents of memory on the system.

A flaw has been identified in glibc. In an extremely rare situation, the getaddrinfo function may access memory that has been freed, resulting in an application crash. This issue is only exploitable when a NSS module implements only the nssgethostbyname2r and nssgetcanonnamer hooks without implementing the nssgethostbyname3r hook. The resolved name should return a large number of IPv6 and IPv4, and the call to the getaddrinfo function should have the AFINET6 address family with AICANONNAME, AIALL and AIV4MAPPED as flags.

A vulnerability was found in libXpm where a vulnerability exists due to a boundary condition, a local user can trigger an out-of-bounds read error and read contents of memory on the system.

A vulnerability was found in libX11 due to an integer overflow within the XCreateImage() function. This flaw allows a local user to trigger an integer overflow and execute arbitrary code with elevated privileges.

An out-of-bounds read flaw was found in w3m, in the Strnewsize function in Str.c. This issue may allow an attacker to cause a denial of service through a crafted HTML file.

A flaw in the Linux Kernel found. For the netfilter, nftablesnewrule when adding a rule with NFTARULECHAINID can lead to use-after-free.

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0ebc1064e4874d5987722a2ddbc18f94aa53b211

A vulnerability was found in subscription-manager that allows local privilege escalation due to inadequate authorization. The D-Bus interface com.redhat.RHSM1 exposes a significant number of methods to all users that could change the state of the registration. By using the com.redhat.RHSM1.Config.SetAll() method, a low-privileged local user could tamper with the state of the registration, by unregistering the system or by changing the current entitlements. This flaw allows an attacker to set arbitrary configuration directives for /etc/rhsm/rhsm.conf, which can be abused to cause a local privilege escalation to an unconfined root.

A vulnerability was found in libX11 due to an infinite loop within the PutSubImage() function. This flaw allows a local user to consume all available system resources and cause a denial of service condition.

Impact I found "multipart/form-data request tampering vulnerability" caused by Content-Disposition "filename" lack of escaping in httparty.

httparty/lib/httparty/request > body.rb > def generatemultipart

https://github.com/jnunemaker/httparty/blob/4416141d37fd71bdba4f37589ec265f55aa446ce/lib/httparty/request/body.rb#L43

By exploiting this problem, the following attacks are possible

An attack that rewrites the "name" field according to the crafted file name, impersonating (overwriting) another field. Attacks that rewrite the filename extension at the time multipart/form-data is generated by tampering with the filename

For example, this vulnerability can be exploited to generate the following Content-Disposition.

Normal Request example: normal input filename: abc.txt generated normal header in multipart/form-data Content-Disposition: form-data; name="avatar"; filename="abc.txt" Malicious Request example malicious input filename: overwritenamefieldandextension.sh"; name="foo"; dummy=".txt generated malicious header in multipart/form-data: Content-Disposition: form-data; name="avatar"; filename="overwritenamefieldandextension.sh"; name="foo"; dummy=".txt"

The Abused Header has multiple name ( avatar & foo ) fields and the "filename" has been rewritten from .txt to .sh .

These problems can result in successful or unsuccessful attacks, depending on the behavior of the parser receiving the request. I have confirmed that the attack succeeds, at least in the following frameworks

Spring (Java) Ktor (Kotlin) Ruby on Rails (Ruby)

The cause of this problem is the lack of escaping of the " (Double-Quote) character in Content-Disposition > filename.

WhatWG's HTML spec has an escaping requirement.

https://html.spec.whatwg.org/#multipart-form-data

For field names and filenames for file fields, the result of the encoding in the previous bullet point must be escaped by replacing any 0x0A (LF) bytes with the byte sequence %0A, 0x0D (CR) with %0D and 0x22 (") with %22. The user agent must not perform any other escapes.

Patches

As noted at the beginning of this section, encoding must be done as described in the HTML Spec.

https://html.spec.whatwg.org/#multipart-form-data

For field names and filenames for file fields, the result of the encoding in the previous bullet point must be escaped by replacing any 0x0A (LF) bytes with the byte sequence %0A, 0x0D (CR) with %0D and 0x22 (") with %22. The user agent must not perform any other escapes.

Therefore, it is recommended that Content-Disposition be modified by either of the following

Before: Content-Disposition: attachment;filename="malicious.sh";dummy=.txt

After: Content-Disposition: attachment;filename="%22malicious.sh%22;dummy=.txt"

https://github.com/jnunemaker/httparty/blob/4416141d37fd71bdba4f37589ec265f55aa446ce/lib/httparty/request/body.rb#L43

filename.gsub('"', '%22')

Also, as for \r, \n, URL Encode is not done, but it is not newlines, so it seemed to be OK. However, since there may be omissions, it is safer to URL encode these as well, if possible. ( \r to %0A and \d to %0D )

PoC

PoC Environment

OS: macOS Monterey(12.3) Ruby ver: ruby 3.1.2p20 httparty ver: 0.20.0 (Python3 - HTTP Request Logging Server)

PoC procedure

(Linux or MacOS is required. This is because Windows does not allow file names containing " (double-quote) .)

1. Create Project $ mkdir my-app $ cd my-app $ gem install httparty

2. Create malicious file

$ touch 'overwritenamefieldandextension.sh"; name="foo"; dummy=".txt'

3. Generate Vuln code

$ vi example.rb

require 'httparty'

filename = 'overwritenamefieldandextension.sh"; name="foo"; dummy=".txt'

HTTParty.post('http://localhost:12345/', body: { name: 'Foo Bar', email: 'example@email.com', avatar: File.open(filename) } )

4. Run Logging Server

I write Python code, but any method will work as long as you can see the HTTP Request Body. (e.g. Debugger, HTTP Logging Server, Packet Capture)

$ vi logging.py from http.server import HTTPServer from http.server import BaseHTTPRequestHandler

class LoggingServer(BaseHTTPRequestHandler):

def doPOST(self): self.sendresponse(200) self.endheaders() self.wfile.write("ok".encode("utf-8"))

contentlength = int(self.headers['Content-Length']) postdata = self.rfile.read(contentlength) print("POST request,\nPath: %s\nHeaders:\n%s\n\nBody:\n%s\n", str(self.path), str(self.headers), postdata.decode('utf-8')) self.wfile.write("POST request for {}".format(self.path).encode('utf-8'))

ip = '127.0.0.1' port = 12345

server = HTTPServer((ip, port), LoggingServer) server.serveforever()

$ python logging.py

5. Run & Logging server

$ run example.rb

Return Request Header & Body:

User-Agent: Ruby Content-Type: multipart/form-data; boundary=------------------------F857UcxRc2J1zFOz Connection: close Host: localhost:12345 Content-Length: 457 --------------------------F857UcxRc2J1zFOz Content-Disposition: form-data; name="name" Foo Bar --------------------------F857UcxRc2J1zFOz Content-Disposition: form-data; name="email" example@email.com --------------------------F857UcxRc2J1zFOz Content-Disposition: form-data; name="avatar"; filename="overwritenamefieldandextension.sh"; name="foo"; dummy=".txt" Content-Type: text/plain abc --------------------------F857UcxRc2J1zFOz--

Content-Disposition: Content-Disposition: form-data; name="avatar"; filename="overwritenamefieldandextension.sh"; name="foo"; dummy=".txt"

name fields is duplicate (avator & foo) filename & extension tampering ( .txt --> .sh )

References

1. I also include a similar report that I previously reported to Firefox. https://bugzilla.mozilla.org/showbug.cgi?id=1556711

2. I will post some examples of frameworks that did not have problems as reference.

Golang https://github.com/golang/go/blob/e0e0c8fe9881bbbfe689ad94ca5dddbb252e4233/src/mime/multipart/writer.go#L144

Spring https://github.com/spring-projects/spring-framework/blob/4cc91e46b210b4e4e7ed182f93994511391b54ed/spring-web/src/main/java/org/springframework/http/ContentDisposition.java#L259-L267

Symphony https://github.com/symfony/symfony/blob/123b1651c4a7e219ba59074441badfac65525efe/src/Symfony/Component/Mime/Header/ParameterizedHeader.php#L128-L133

For more information If you have any questions or comments about this advisory: Email us at kumagoroalice@yahoo.co.jp

A flaw was found in the QEMU built-in VNC server while processing ClientCutText messages. A wrong exit condition may lead to an infinite loop when inflating an attacker controlled zlib buffer in the inflatebuffer function. This could allow a remote authenticated client who is able to send a clipboard to the VNC server to trigger a denial of service.

An out-of-bounds read in MyEID driver handling encryption using symmetric keys. An attacker with physical access to the computer running opensc and crafted USB device or smart card that would present the system with specially crafted responses to the APDUs so they are considered a high-complexity and low-severity.

This issue is in the code handling symmetric keys, which are not widely used for example for desktop login so most of the deployments are not affected.

https://github.com/OpenSC/OpenSC/issues/2792#issuecomment-1674806651 https://github.com/OpenSC/OpenSC/wiki/OpenSC-security-advisories https://github.com/OpenSC/OpenSC/releases/tag/0.24.0-rc1

An improper input validation flaw was found in the eBPF subsystem in the Linux kernel. The issue occurs due to a lack of proper validation of dynamic pointers within user-supplied eBPF programs prior to executing them. This may allow an attacker with CAPBPF privileges to escalate privileges and execute arbitrary code in the context of the kernel.

An out-of-bounds read vulnerability was found in Netfilter Connection Tracking (conntrack) in the Linux kernel. This flaw allows a remote user to disclose sensitive information via the DCCP protocol.

A flaw was found in the XFRM subsystem in the Linux kernel. The specific flaw exists within the processing of state filters, which can result in a read past the end of an allocated buffer. This flaw allows a local privileged (CAPNETADMIN) attacker to trigger an out-of-bounds read, potentially leading to an information disclosure.

A flaw was found in the exFAT driver of the Linux kernel. The vulnerability exists in the implementation of the file name reconstruction function, which is responsible for reading file name entries from a directory index and merging file name parts belonging to one file into a single long file name. Since the file name characters are copied into a stack variable, a local privileged attacker could use this flaw to overflow the kernel stack.

A flaw in the Linux Kernel found. Improper element removal in function nftpipaporemove when insert an element without a NFTSETEXTKEYEND that can lead to use-after-free.

Reference: https://patchwork.ozlabs.org/project/netfilter-devel/patch/20230719190824.21196-1-fw@strlen.de/

A flaw was found in glibc. When the getaddrinfo function is called with the AFUNSPEC address family and the system is configured with no-aaaa mode via /etc/resolv.conf, a DNS response via TCP larger than 2048 bytes can potentially disclose stack contents through the function returned address data, and may cause a crash.

A flaw was found in the Netfilter subsystem in the Linux kernel. The nfnlosfaddcallback function did not validate the user mode controlled optnum field. This flaw allows a local privileged (CAPNETADMIN) attacker to trigger an out-of-bounds read, leading to a crash or information disclosure.

A buffer overflow was discovered in the GNU C Library's dynamic loader ld.so while processing the GLIBCTUNABLES environment variable. This issue could allow a local attacker to use maliciously crafted GLIBCTUNABLES environment variables when launching binaries with SUID permission to execute code with elevated privileges.

A race condition flaw was found in sssd where the GPO policy is not consistently applied for authenticated users. This may lead to improper authorization issues, granting or denying access to resources inappropriately.

A flaw was found in the Netfilter subsystem of the Linux kernel. A race condition between IPSETCMDADD and IPSETCMDSWAP can lead to a kernel panic due to the invocation of ipsetput on a wrong set. This issue may allow a local user to crash the system.

A flaw was found in the Netfilter subsystem in the Linux kernel. The sctpmtcheck did not validate the flagcount field. This flaw allows a local privileged (CAPNETADMIN) attacker to trigger an out-of-bounds read, leading to a crash or information disclosure.

A flaw found in the Linux Kernel. The tun/tap sockets have their socket UID hardcoded to 0 due to a type confusion in their initialization function. While it will be often correct, as tuntap devices require CAPNETADMIN, it may not always be the case, e.g., a non-root user only having that capability. This would make tun/tap sockets being incorrectly treated in filtering/routing decisions, possibly bypassing network filters. The original fix for the CVE-2023-1076 was incorrect. The problem is that the following upstream commits (that were fix for the CVE-2023-1076) - a096ccca6e50 ("tun: tunchropen(): correctly initialize socket uid"), - 66b2c338adce ("tap: tapopen(): correctly initialize socket uid"), pass "inode->iuid" to sockinitdatauid() as the last parameter and that turns out to be entirely bogus.

References: https://lore.kernel.org/all/20230731164237.48365-1-lersek@redhat.com/ https://lore.kernel.org/all/20230731164237.48365-2-lersek@redhat.com/ https://lore.kernel.org/all/20230731164237.48365-3-lersek@redhat.com/

A flaw was found in ipv4senddestunreach() due to NULL pointer derefence due to a missing edge-case check.

A flaw was found in the Netfilter subsystem in the Linux kernel. The xtu32 module did not validate the fields in the xtu32 structure. This flaw allows a local privileged attacker to trigger an out-of-bounds read by setting the size fields with a value beyond the array boundaries, leading to a crash or information disclosure.

A buffer overflow flaw was found in base/gdevdevn.c:1973 in devnpcxwriterle() in ghostscript. This issue may allow a local attacker to cause a denial of service via outputting a crafted PDF file for a DEVN device with gs.