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CVE-2017-7783

Published: Jun 11, 2018Updated: Nov 21, 2024 Sources: CVE List NVDCWE-20
7.5HIGH
NVD MITRE
EPSS Score
9.9%
Top 4.7%
CISA KEV
Not in KEV
Exploits
2 Known
Remediation
Patch Available
Self-Check
OpenVAS

Description

If a long user name is used in a username/password combination in a site URL (such as " http://UserName:Password@example.com"), the resulting modal prompt will hang in a non-responsive state or crash, causing a denial of service. This vulnerability affects Firefox < 55.

In plain language

AI Worth attention

CVE-2017-7783 can let a remote attacker freeze or crash Firefox by sending it a specially crafted website link with an extremely long username; most small businesses should act only if staff use a Firefox version older than 55.

Executive summary

In Firefox, a remote attacker can trigger a denial of service by using a crafted URL with an excessively long username in a user:pass@ URL, causing the browser’s security prompt/modal to hang or crash (Firefox < 55.0).

If affected, business impact
Workstation browser freezeDisruption to daily operationsLoss of access to web appsPotential emergency workarounds

What to do now

  1. Check each workstation/server running Firefox and note the Firefox version.
  2. If any Firefox version is older than 55, update Firefox to 55.0 (or later) right away.
  3. After updating, try opening a normal login URL and confirm the browser no longer hangs when security prompts appear.
  4. If you can’t update immediately, limit exposure by avoiding clicking or loading untrusted links that include user:pass@ style URLs.
Patch / advisory Usually a quick update

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
Open in CVSS calculator →

Weaknesses

CWE-20

Affected Products

Mozilla
oss-project·USaka mozilla corp.
FirefoxOn-premDesktop App
Consumer Software / browser
and 1 more affected products View all →

Exploitability

2 exploit sources identified

Exploit details including PoC links, Metasploit modules, and scanner templates are available after registration.

View exploit details
Official Patch Available
Is your org exposed to CVE-2017-7783?We can run the check for you — a free external exposure review, no install. Check my exposure

Attack Graph

Products CVE Techniques Tactics

Click technique nodes for MITRE ATT&CK details · drag to pan · Ctrl/⌘ + scroll to zoom, or go fullscreen.

MITRE ATT&CK

1 technique
Initial Access
View detailed technique mapping

References

http://www.securityfocus.com/bid/100401
securityfocus.com
http://www.securitytracker.com/id/1039124
securitytracker.com
https://bugzilla.mozilla.org/show_bug.cgi?id=1360842
bugzilla.mozilla.org
and 2 more references View all →

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