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Two Guys and an Opinion

'Solarwinds123'?

Two Guys and an Opinion
Two Guys and an Opinion

With the fallout of the Solarwinds breach continuing to grab the headlines, we discuss the concept of 'supply-chain compromise' and why it's such a favoured attack vector.

Also covered is the highly sophisticated zero-day exploit chaining attack perpetrated by a Chinese state-sponsored group called HAFNIUM against on-premise MS Exchange servers.

Oh, and Richard craves a beer-garden.....

Show notes:

As mentioned in this episode, the critical MS Exchange CVEs are:

  • CVE-2021-26855 is a server-side request forgery (SSRF) vulnerability in Exchange that allows an attacker to send arbitrary HTTP requests and authenticate as the Exchange server.
  • CVE-2021-26857 is an insecure deserialization vulnerability in the Unified Messaging service. Insecure deserialization is where untrusted user-controllable data is deserialized by a program. Exploiting this vulnerability gives an attacker the ability to run code as SYSTEM on the Exchange server. This requires administrator permission or another vulnerability to exploit.
  • CVE-2021-26858 is a post-authentication arbitrary file write vulnerability in Exchange. If an attacker could authenticate with the Exchange server, they could use this vulnerability to write a file to any path on the server. They could authenticate by exploiting the CVE-2021-26855 SSRF vulnerability or by compromising a legitimate admin’s credentials.
  • CVE-2021-27065 is a post-authentication arbitrary file write vulnerability in Exchange. An attacker who can authenticate with the Exchange server can use this vulnerability to write a file to any path on the server. They could authenticate by exploiting the CVE-2021-26855 SSRF vulnerability or by compromising a legitimate admin’s credentials.

Also included in the out-of-band update were three additional remote code execution vulnerabilities in Microsoft Exchange. These additional vulnerabilities are not known to be part of the HAFNIUM-attributed threat campaign but should be remediated with the same urgency nonetheless:


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