Microsoft Exchange Server 2013 CU23/2016 CU18/2016 CU19/2019 CU7/2019 CU8 ProxyLogon unknown vulnerability
CVSS Meta Temp Score | Current Exploit Price (≈) | CTI Interest Score |
---|---|---|
8.9 | $0-$5k | 0.03 |
A vulnerability was found in Microsoft Exchange Server 2013 CU23/2016 CU18/2016 CU19/2019 CU7/2019 CU8 (Groupware Software). It has been classified as very critical. This is going to have an impact on confidentiality, and integrity.
The weakness was disclosed 03/02/2021 as confirmed security guidance (Website). The advisory is shared for download at portal.msrc.microsoft.com. This vulnerability is traded as CVE-2021-26855. Technical details are unknown but a public exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 12/13/2021).
A public exploit has been developed by Jang (testanull) in Python and been published 2 weeks after the advisory. The exploit is shared for download at testbnull.medium.com. It is declared as functional. As 0-day the estimated underground price was around $25k-$100k.
Applying a patch is able to eliminate this problem. A possible mitigation has been published immediately after the disclosure of the vulnerability.
Product
Type
Vendor
Name
Version
License
CPE 2.3
CPE 2.2
Video
Youtube: Not available anymoreCVSSv4
VulDB CVSS-B Score: 🔍VulDB CVSS-BT Score: 🔍
VulDB Vector: 🔍
VulDB Reliability: 🔍
CVSSv3
VulDB Meta Base Score: 9.3VulDB Meta Temp Score: 8.9
VulDB Base Score: 9.1
VulDB Temp Score: 8.4
VulDB Vector: 🔍
VulDB Reliability: 🔍
Vendor Base Score (Microsoft): 9.1
Vendor Vector (Microsoft): 🔍
NVD Base Score: 9.8
NVD Vector: 🔍
CVSSv2
AV | AC | Au | C | I | A |
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💳 | 💳 | 💳 | 💳 | 💳 | 💳 |
💳 | 💳 | 💳 | 💳 | 💳 | 💳 |
💳 | 💳 | 💳 | 💳 | 💳 | 💳 |
Vector | Complexity | Authentication | Confidentiality | Integrity | Availability |
---|---|---|---|---|---|
unlock | unlock | unlock | unlock | unlock | unlock |
unlock | unlock | unlock | unlock | unlock | unlock |
unlock | unlock | unlock | unlock | unlock | unlock |
VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍
NVD Base Score: 🔍
Exploiting
Class: UnknownCWE: Unknown
ATT&CK: Unknown
Local: No
Remote: Yes
Availability: 🔍
Access: Public
Status: Functional
Author: Jang (testanull)
Programming Language: 🔍
Download: 🔍
EPSS Score: 🔍
EPSS Percentile: 🔍
Price Prediction: 🔍
Current Price Estimation: 🔍
0-Day | unlock | unlock | unlock | unlock |
---|---|---|---|---|
Today | unlock | unlock | unlock | unlock |
Threat Intelligence
Interest: 🔍Active Actors: 🔍
Active APT Groups: 🔍
Countermeasures
Recommended: PatchStatus: 🔍
Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍
Exploit Delay Time: 🔍
Timeline
02/08/2021 🔍03/02/2021 🔍
03/02/2021 🔍
03/03/2021 🔍
03/11/2021 🔍
12/13/2021 🔍
Sources
Vendor: microsoft.comAdvisory: portal.msrc.microsoft.com
Status: Confirmed
CVE: CVE-2021-26855 (🔍)
scip Labs: https://www.scip.ch/en/?labs.20161013
Entry
Created: 03/03/2021 08:22Updated: 12/13/2021 11:23
Changes: 03/03/2021 08:22 (33), 03/03/2021 08:25 (19), 03/06/2021 12:17 (2), 03/12/2021 07:43 (9), 03/14/2021 12:02 (18), 12/13/2021 11:23 (2)
Complete: 🔍
Committer: misc