SMTP service in (1) Microsoft Windows 2000 and (2) Internet Mail Connector (IMC) in Exchange Server 5.5 does not properly handle responses t
SMTP service in (1) Microsoft Windows 2000 and (2) Internet Mail Connector (IMC) in Exchange Server 5.5 does not properly handle responses to NTLM authentication, which allows remote attackers to perform mail relaying via an SMTP AUTH command using null session credentials.
- Published
- Mar 8, 2002
- Updated
- Jun 16, 2026
- EPSS
- 22.4% · 98th percentile
- CWE
- CWE-294
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Report tools
Action score
37
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 7 / 30 · 22.4%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| microsoft | exchange server | cpe:2.3:a:microsoft:exchange_server |
| microsoft | windows 2000 | cpe:2.3:o:microsoft:windows_2000 |
Using exchange server? Add it to your stack and be the first to know about CVEs like this one. (Email server)
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- microsoft exchange server5.5
Same product
microsoft: all recordsOther highest-scoring records for the same primary product.
- CVE-2021-34523Microsoft Exchange Server Elevation of Privilege VulnerabilityKEV96Now
- CVE-2021-34473Microsoft Exchange Server Remote Code Execution VulnerabilityKEV96Now
- CVE-2021-26855Microsoft Exchange Server Remote Code Execution VulnerabilityKEV96Now
- CVE-2022-41040Microsoft Exchange Server Elevation of Privilege VulnerabilityKEV95Now
- CVE-2020-0688A remote code execution vulnerability exists in Microsoft Exchange software when the software fails to properly handle objects in memory, akKEV95Now
- CVE-2021-42321Microsoft Exchange Server Remote Code Execution VulnerabilityKEV93Now
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- P · data can be read
- Integrity
- P · data or configuration can be modified
- Availability
- P · the service can be disrupted
- Attack complexity
- Low
- Confidentiality impact
- P
- Integrity impact
- P
- Availability impact
- P
Weakness class (CWE)
CWE-294 · Authentication Bypass by Capture-replayCVSS vector
AV:N/AC:L/Au:N/C:P/I:P/A:P
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Session SidejackingCAPEC-102likelihood: High · High
- KerberoastingCAPEC-509High
- Remote Services with Stolen CredentialsCAPEC-555Very High
- Windows Admin Shares with Stolen CredentialsCAPEC-561
- Reusing Session IDs (aka Session Replay)CAPEC-60likelihood: High · High
- Use of Captured Hashes (Pass The Hash)CAPEC-644likelihood: Medium · High
- Use of Captured Tickets (Pass The Ticket)CAPEC-645likelihood: Low · High
- Use of Known Kerberos CredentialsCAPEC-652likelihood: Medium · High
ATT&CK techniques
- Remote ServicesT1021
- Remote Services:SMB/Windows Admin SharesT1021.002
- Email Collection:Remote Email CollectionT1114.002
- External Remote ServicesT1133
- Access Token Manipulation:Token Impersonation/TheftT1134.001
- Use Alternate Authentication Material:Pass The HashT1550.002
- Use Alternate Authentication Material:Pass The TicketT1550.003
- Use Alternate Authentication Material:Web Session CookieT1550.004
- Adversary-in-the-MiddleT1557
- Steal or Forge Kerberos TicketsT1558
- Steal or Forge Kerberos Tickets:KerberoastingT1558.003
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
- marc.info/?l=bugtraq&m=101501580409373&w=2
- www.securityfocus.com/bid/4205
- docs.microsoft.com/en-us/security-updates/securitybulletins/2002/ms02-011
Vendor advisories and official records. Exploit/PoC links are deliberately left out.