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Microsoft on Friday disclosed that a single activity group in August 2022 achieved initial access and breached Exchange servers by chaining the two newly disclosed zero-day flaws in a limited set of attacks aimed at less than 10 organizations globally. "These attacks installed the Chopper web shell to facilitate hands-on-keyboard access, which the attackers used to perform Active Directory

SonicJS through 0.6.0 allows file overwrite. It has the following mutations that are used for updating files: fileCreate and fileUpdate. Both of these mutations can be called without any authentication to overwrite any files on a SonicJS application, leading to Arbitrary File Write and Delete.

The package css-what before 2.1.3 is vulnerable to Regular Expression Denial of Service (ReDoS) due to the use of insecure regular expression in the `re_attr` variable of index.js. The exploitation of this vulnerability could be triggered via the parse function.

The package react-native-reanimated before 3.0.0-rc.1 is vulnerable to Regular Expression Denial of Service (ReDoS) due to improper usage of regular expression in the parser of Colors.js.

### Impact If the untrusted v8 cached data is passed to the API through CachedDataOptions, the attackers can bypass the sandbox and run arbitrary code in the nodejs process. There are currently no known fixed versions or workarounds.

## Impact An attacker cooperating with a malicious homeserver could interfere with the verification flow between two users, injecting its own cross-signing user identity in place of one of the users’ identities, leading to the other device trusting/verifying the user identity under the control of the homeserver instead of the intended one. The vulnerability is a bug in the matrix-js-sdk, caused by checking and signing user identities and devices in two separate steps, and inadequately fixing the keys to be signed between those steps. Even though the attack is partly made possible due to the design decision of treating cross-signing user identities as Matrix devices on the server side (with their device ID set to the public part of the user identity key), no other examined implementations were vulnerable. ## Patches The matrix-js-sdk has been modified to double check that the key signed is the one that was verified instead of just referencing the key by ID. An additional check has ...

While organizations wait for an official patch for the two zero-day flaws in Microsoft Exchange, they should scan their networks for signs of exploitation and apply these mitigations.

Cisco Talos has released new coverage to detect and prevent the exploitation of two recently disclosed vulnerabilities collectively referred to as "ProxyNotShell," affecting Microsoft Exchange Servers 2013, 2016 and 2019. One of these vulnerabilities could allow an attacker to execute remote code on the targeted server. Limited exploitation of these vulnerabilities in the wild has been reported. CVE-2022-41040 is a Server Side Request Forgery (SSRF) vulnerability, while CVE-2022-41082 enables Remote Code Execution (RCE) when PowerShell is accessible to the attackers. While no fixes or patches are available yet, Microsoft has provided mitigations for on-premises Microsoft Exchange users on Sept. 29, 2022. Even organizations that use Exchange Online may still be affected if they run a hybrid server. Cisco Talos is closely monitoring the recent reports of exploitation attempts against these vulnerabilities and strongly recommends users implement mitigation steps while waiting for securit...

Even organizations that use Exchange Online may still be affected if they run a hybrid server.

Talos is publishing a glimpse into the most prevalent threats we've observed between Sept. 23 and Sept. 30.