CVE-2021-42761

published 2023-02-16

CVE-2021-42761: A condition for session fixation vulnerability [CWE-384] in the session management of FortiWeb versions 6.4 all versions, 6.3.0 through 6.3.16, 6.2.0 through…

Priority P2 61 critical 9.8 CVSS 3.1

AV N AC L PR N UI N S U C H I H A H

A condition for session fixation vulnerability [CWE-384] in the session management of FortiWeb versions 6.4 all versions, 6.3.0 through 6.3.16, 6.2.0 through 6.2.6, 6.1.0 through 6.1.2, 6.0.0 through 6.0.7, 5.9.0 through 5.9.1 may allow a remote, unauthenticated attacker to infer the session identifier of other users and possibly usurp their session.

Affected

17 ranges

Vendor	Product	Version range	Fixed in
fortinet	fortiweb	—	—
fortinet	fortiweb	>= 5.6.0 < 5.9.2	5.9.2
fortinet	fortiweb	5.6.0 – 5.6.2	—
fortinet	fortiweb	5.7.0 – 5.7.3	—
fortinet	fortiweb	5.8.0 – 5.8.3	—
fortinet	fortiweb	5.8.5 – 5.8.7	—
fortinet	fortiweb	5.9.0 – 5.9.1	—
fortinet	fortiweb	>= 6.0.0 < 6.0.8	6.0.8
fortinet	fortiweb	6.0.0 – 6.0.7	—
fortinet	fortiweb	>= 6.1.0 < 6.1.3	6.1.3
fortinet	fortiweb	6.1.0 – 6.1.2	—
fortinet	fortiweb	>= 6.2.0 < 6.2.7	6.2.7
fortinet	fortiweb	6.2.0 – 6.2.6	—
fortinet	fortiweb	>= 6.3.0 < 6.3.17	6.3.17
fortinet	fortiweb	6.3.0 – 6.3.16	—
fortinet	fortiweb	>= 6.4.0 < 7.0.0	7.0.0
fortinet	fortiweb	6.4.0 – 6.4.2	—

Detection & IOCs extracted from sources · hover to see the quote

• → Target product is FortiWeb; monitor for session fixation attempts against FortiWeb session management — an unauthenticated attacker may attempt to infer or reuse session identifiers of authenticated users ↗
• → CWE-384 (Session Fixation) — look for anomalous session token reuse or session ID patterns that appear predictable/sequential in FortiWeb access logs, particularly from unauthenticated source IPs ↗

• · All FortiWeb 6.4.x versions are affected; also affected are 6.3.0–6.3.16, 6.2.0–6.2.6, 6.1.0–6.1.2, 6.0.0–6.0.7, and 5.9.0–5.9.1 — verify patched versions are deployed ↗
• · CVSS score is 9.0 (Critical) and exploitation requires no authentication, making unpatched internet-facing FortiWeb instances high-priority targets ↗

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CWE-384