AA22-228A: Threat Actors Exploiting Multiple CVEs Against Zimbra Collaboration Suite

Cybersecurity
Original release date: August 16, 2022 | Last revised: September 27, 2022
Summary Actions for ZCS administrators to take today to mitigate malicious
cyber activity: • Patch all systems and prioritize patching known exploited
vulnerabilities . • Deploy detection signatures and hunt for indicators of
compromise (IOCs). • If ZCS was compromised, remediate malicious activity. The
Cybersecurity and Infrastructure Security Agency (CISA ) and the Multi-State
Information Sharing & Analysis Center (MS-ISAC ) are publishing this joint
Cybersecurity Advisory (CSA) in response to active exploitation of multiple
Common Vulnerabilities and Exposures (CVEs) against Zimbra Collaboration Suite
(ZCS), an enterprise cloud-hosted collaboration software and email platform.
CVEs currently being exploited against ZCS include: CVE-2022-24682
CVE-2022-27924 CVE-2022-27925 chained with CVE-2022-37042 CVE-2022-30333 Cyber
threat actors may be targeting unpatched ZCS instances in both government and
private sector networks. CISA and the MS-ISAC strongly urge users and
administrators to apply the guidance in the Recommendations section of this
CSA to help secure their organization’s systems against malicious cyber
activity. CISA and the MS-ISAC encourage organizations who did not immediately
update their ZCS instances upon patch release, or whose ZCS instances were
exposed to the internet, to assume compromise and hunt for malicious activity
using the third-party detection signatures in the Detection Methods section of
this CSA. Organizations that detect potential compromise should apply the
steps in the Incident Response section of this CSA. Update September 27 , 2022
: This CSA has been updated with additional IOCs. For a downloadable copy of
the IOCs, see the following Malware Analysis Reports (MARs): MAR-10400779-1
MAR-10400779-2 MAR-10401765-1 Update End Download the PDF version of this
report: pdf, 427 kb Download the IOCs: .stix 14 kb Technical Details
CVE-2022-27924 CVE-2022-27924 is a high-severity vulnerability enabling an
unauthenticated malicious actor to inject arbitrary memcache commands into a
targeted ZCS instance and cause an overwrite of arbitrary cached entries. The
actor can then steal ZCS email account credentials in cleartext form without
any user interaction. With valid email account credentials in an organization
not enforcing multifactor authentication (MFA), a malicious actor can use
spear phishing, social engineering, and business email compromise (BEC)
attacks against the compromised organization. Additionally, malicious actors
could use the valid account credentials to open webshells and maintain
persistent access. On March 11, 2022, researchers from SonarSource announced
the discovery of this ZCS vulnerability. Zimbra issued fixes for releases
8.8.15 and 9.0 on May 10, 2022. Based on evidence of active exploitation, CISA
added this vulnerability to the Known Exploited Vulnerabilities Catalog on
August 4, 2022. Due to ease of exploitation, CISA and the MS-ISAC expect to
see widespread exploitation of unpatched ZCS instances in government and
private networks. CVE-2022-27925 and CVE-2022-37042 CVE-2022-27925 is a high
severity vulnerability in ZCS releases 8.8.15 and 9.0 that have mboximport
functionality to receive a ZIP archive and extract files from it. An
authenticated user has the ability to upload arbitrary files to the system
thereby leading to directory traversal.[1 ] On August 10, 2022, researchers
from Volexity reported widespread exploitation—against over 1,000 ZCS
instances—of CVE-2022-27925 in conjunction with CVE-2022-37042.[2 ] CISA added
both CVEs to the Known Exploited Vulnerabilities Catalog on August 11, 2022.
CVE 2022 37042 is an authentication bypass vulnerability that affects ZCS
releases 8.8.15 and 9.0. CVE 2022 37042 could allow an unauthenticated
malicious actor access to a vulnerable ZCS instance. According to Zimbra, CVE
2022 37042 is found in the MailboxImportServlet function.[3][ 4 ] Zimbra
issued fixes in late July 2022. CVE-2022-30333 CVE-2022-30333 is a high-
severity directory traversal vulnerability in RARLAB UnRAR on Linux and UNIX
allowing a malicious actor to write to files during an extract (unpack)
operation. A malicious actor can exploit CVE-2022-30333 against a ZCS server
by sending an email with a malicious RAR file. Upon email receipt, the ZCS
server would automatically extract the RAR file to check for spam or
malware.[5 ] Any ZCS instance with unrar installed is vulnerable to
CVE-2022-30333. Researchers from SonarSource shared details about this
vulnerability in June 2022.[6] Zimbra made configuration changes to use the
7zip program instead of unrar .[7] CISA added CVE-2022-3033 to the Known
Exploited Vulnerabilities Catalog on August 9, 2022. Based on industry
reporting, a malicious cyber actor is selling a cross-site scripting (XSS)
exploit kit for the ZCS vulnerability to CVE 2022 30333. A Metasploit module
is also available that creates a RAR file that can be emailed to a ZCS server
to exploit CVE-2022-30333.[8 ] CVE-2022-24682 CVE-2022-24682 is a medium-
severity vulnerability that impacts ZCS webmail clients running releases
before 8.8.15 patch 30 (update 1), which contain a cross-site scripting (XSS)
vulnerability allowing malicious actors to steal session cookie files.
Researchers from Volexity shared this vulnerability on February 3, 2022[9 ],
and Zimbra issued a fix on February 4, 2022.[10 ] CISA added this
vulnerability to the Known Exploited Vulnerabilities Catalog on February 25,
2022. DETECTION METHODS Note: CISA and the MS-ISAC will update this section
with additional IOCs and signatures as further information becomes available.
CISA recommends administrators, especially at organizations that did not
immediately update their ZCS instances upon patch release, to hunt for
malicious activity using the following third-party detection signatures:
Update September 27 , 2022 : Hunt for IOCs including: IP Addresses Note
62.113.255[.]70 New September 27, 2022: Used by cyber actors during August
15-26, 2022 while attempting to exploit CVE-2022-27925 and CVE-2022-37042
185.112.83[.]77 New September 27, 2022: Used by cyber actors during August
15-26, 2022 while attempting to exploit CVE-2022-27925 and CVE-2022-37042
207.148.76[.]235 A Cobalt Strike command and control (C2) domain
209.141.56[.]90 New September 27, 2022 Update August 23 , 2022 : Deploy Snort
signatures to detect malicious activity: alert tcp any any -> any any
(msg:”ZIMBRA: HTTP POST content data ‘.jsp’ file'”; sid:x;
flow:established,to_server; content:”POST”; http_method;
content:”|2f|service|2f|extension|2f|backup|2f|mboximport”; nocase; http_uri;
content:”file|3a|”; nocase; http_client_body; content:”|2e|jsp”;
http_client_body; fast_pattern; classtype:http-content;
reference:cve,2022-30333;) alert tcp any any -> any any (msg:”ZIMBRA: Client
HTTP Header ‘QIHU 360SE'”; sid:x; flow:established,to_server; content:”POST”;
http_method; content:”|2f|service|2f|extension|2f|backup|2f|mboximport”;
nocase; http_uri; content:”QIHU|20|360SE”; nocase; http_header; fast_pattern;
classtype:http-header; reference:cve,2022-30333;) alert tcp any any -> any any
(msg:”ZIMBRA:HTTP GET URI for Zimbra Local Config”; sid:x;
flow:established,to_server;
content:”/public/jsp/runas.jsp?pwd=zim&i;=/opt/zimbra/bin/zmlocalconfig|3a|-s”;
http_uri; classtype:http-uri; reference:cve,2022-30333;) Deploy third-party
YARA rules to detect malicious activity: See Volexity’s Mass Exploitation of
(Un)authenticated Zimbra RCE: CVE-2022-27925 Mitigations CISA and the MS-ISAC
recommend organizations upgrade to the latest ZCS releases as noted on Zimbra
Security – News & Alerts and Zimbra Security Advisories . See Volexity’s Mass
Exploitation of (Un)authenticated Zimbra RCE: CVE-2022-27925 for mitigation
steps. Additionally, CISA and the MS-ISAC recommend organizations apply the
following best practices to reduce risk of compromise: Maintain and test an
incident response plan. Ensure your organization has a vulnerability
management program in place and that it prioritizes patch management and
vulnerability scanning of known exploited vulnerabilities . Note: CISA’s Cyber
Hygiene Services (CyHy) are free to all state, local, tribal, and territorial
(SLTT) organizations, as well as public and private sector critical
infrastructure organizations: cisa.gov/cyber-hygiene-services . Properly
configure and secure internet-facing network devices. Do not expose management
interfaces to the internet. Disable unused or unnecessary network ports and
protocols. Disable/remove unused network services and devices. Adopt zero-
trust principles and architecture , including: Micro-segmenting networks and
functions to limit or block lateral movements. Enforcing phishing-resistant
(MFA) for all users and virtual private network (VPN) connections. Restricting
access to trusted devices and users on the networks. INCIDENT RESPONSE If an
organization’s system has been compromised by active or recently active threat
actors in their environment, CISA and the MS-ISAC recommend the following
initial steps: Collect and review artifacts , such as running
processes/services, unusual authentications, and recent network connections.
Quarantine or take offline potentially affected hosts . Reimage compromised
hosts . Provision new account credentials . Report the compromise to CISA via
CISA’s 24/7 Operations Center (report@cisa.gov or 888-282-0870). SLTT
government entities can also report to the MS-ISAC (SOC@cisecurity.org or
866-787-4722). See the joint CSA from the cybersecurity authorities of
Australia, Canada, New Zealand, the United Kingdom, and the United States on
Technical Approaches to Uncovering and Remediating Malicious Activity for
additional guidance on hunting or investigating a network, and for common
mistakes in incident handling. CISA and the MS-ISAC also encourage government
network administrators to see CISA’s Federal Government Cybersecurity Incident
and Vulnerability Response Playbooks . Although tailored to federal civilian
branch agencies, these playbooks provide detailed operational procedures for
planning and conducting cybersecurity incident and vulnerability response
activities. ACKNOWLEDGEMENTS CISA and the MS-ISAC would like to thank Volexity
and Secureworks for their contributions to this advisory. DISCLAIMER The
information in this report is being provided “as is” for informational
purposes only. CISA and the MS-ISAC do not provide any warranties of any kind
regarding this information. CISA and the MS-ISAC do not endorse any commercial
product or service, including any subjects of analysis. Any reference to
specific commercial products, processes, or services by service mark,
trademark, manufacturer, or otherwise, does not constitute or imply
endorsement, recommendation, or favoring. References [1] CVE-2022-27925 detail
[2] Mass exploitation of (un)authenticated Zimbra RCE: CVE-2022-27925 [3]
CVE-2022-37042 detail [4] Authentication bypass in MailboxImportServlet
vulnerability [5] CVE-2022-30333 detail [6] UnRAR vulnerability exploited in
the wild, likely against Zimbra servers [7] Zimbra Collaboration Kepler 9.0.0
patch 25 GA release [8] Zimbra UnRAR path traversal [9] Operation EmailThief:
Active exploitation of zero-day XSS vulnerability in Zimbra [10] Hotfix
available 5 Feb for zero-day exploit vulnerability in Zimbra 8.8.15 Revisions
August 16, 2022: Initial Version August 22, 2022: Added Snort Signatures
August 23, 2022: Updated Detection Methods Snort Signatures This product is
provided subject to this Notification and this Privacy & Use policy.Original release date: August 16, 2022 | Last revised: September 27, 2022
Summary Actions for ZCS administrators to take today to mitigate malicious
cyber activity: • Patch all systems and prioritize patching known exploited
vulnerabilities . • Deploy detection signatures and hunt for indicators of
compromise (IOCs). • If ZCS was compromised, remediate malicious activity. The
Cybersecurity and Infrastructure Security Agency (CISA ) and the Multi-State
Information Sharing & Analysis Center (MS-ISAC ) are publishing this joint
Cybersecurity Advisory (CSA) in response to active exploitation of multiple
Common Vulnerabilities and Exposures (CVEs) against Zimbra Collaboration Suite
(ZCS), an enterprise cloud-hosted collaboration software and email platform.
CVEs currently being exploited against ZCS include: CVE-2022-24682
CVE-2022-27924 CVE-2022-27925 chained with CVE-2022-37042 CVE-2022-30333 Cyber
threat actors may be targeting unpatched ZCS instances in both government and
private sector networks. CISA and the MS-ISAC strongly urge users and
administrators to apply the guidance in the Recommendations section of this
CSA to help secure their organization’s systems against malicious cyber
activity. CISA and the MS-ISAC encourage organizations who did not immediately
update their ZCS instances upon patch release, or whose ZCS instances were
exposed to the internet, to assume compromise and hunt for malicious activity
using the third-party detection signatures in the Detection Methods section of
this CSA. Organizations that detect potential compromise should apply the
steps in the Incident Response section of this CSA. Update September 27 , 2022
: This CSA has been updated with additional IOCs. For a downloadable copy of
the IOCs, see the following Malware Analysis Reports (MARs): MAR-10400779-1
MAR-10400779-2 MAR-10401765-1 Update End Download the PDF version of this
report: pdf, 427 kb Download the IOCs: .stix 14 kb Technical Details
CVE-2022-27924 CVE-2022-27924 is a high-severity vulnerability enabling an
unauthenticated malicious actor to inject arbitrary memcache commands into a
targeted ZCS instance and cause an overwrite of arbitrary cached entries. The
actor can then steal ZCS email account credentials in cleartext form without
any user interaction. With valid email account credentials in an organization
not enforcing multifactor authentication (MFA), a malicious actor can use
spear phishing, social engineering, and business email compromise (BEC)
attacks against the compromised organization. Additionally, malicious actors
could use the valid account credentials to open webshells and maintain
persistent access. On March 11, 2022, researchers from SonarSource announced
the discovery of this ZCS vulnerability. Zimbra issued fixes for releases
8.8.15 and 9.0 on May 10, 2022. Based on evidence of active exploitation, CISA
added this vulnerability to the Known Exploited Vulnerabilities Catalog on
August 4, 2022. Due to ease of exploitation, CISA and the MS-ISAC expect to
see widespread exploitation of unpatched ZCS instances in government and
private networks. CVE-2022-27925 and CVE-2022-37042 CVE-2022-27925 is a high
severity vulnerability in ZCS releases 8.8.15 and 9.0 that have mboximport
functionality to receive a ZIP archive and extract files from it. An
authenticated user has the ability to upload arbitrary files to the system
thereby leading to directory traversal.[1 ] On August 10, 2022, researchers
from Volexity reported widespread exploitation—against over 1,000 ZCS
instances—of CVE-2022-27925 in conjunction with CVE-2022-37042.[2 ] CISA added
both CVEs to the Known Exploited Vulnerabilities Catalog on August 11, 2022.
CVE 2022 37042 is an authentication bypass vulnerability that affects ZCS
releases 8.8.15 and 9.0. CVE 2022 37042 could allow an unauthenticated
malicious actor access to a vulnerable ZCS instance. According to Zimbra, CVE
2022 37042 is found in the MailboxImportServlet function.[3][ 4 ] Zimbra
issued fixes in late July 2022. CVE-2022-30333 CVE-2022-30333 is a high-
severity directory traversal vulnerability in RARLAB UnRAR on Linux and UNIX
allowing a malicious actor to write to files during an extract (unpack)
operation. A malicious actor can exploit CVE-2022-30333 against a ZCS server
by sending an email with a malicious RAR file. Upon email receipt, the ZCS
server would automatically extract the RAR file to check for spam or
malware.[5 ] Any ZCS instance with unrar installed is vulnerable to
CVE-2022-30333. Researchers from SonarSource shared details about this
vulnerability in June 2022.[6] Zimbra made configuration changes to use the
7zip program instead of unrar .[7] CISA added CVE-2022-3033 to the Known
Exploited Vulnerabilities Catalog on August 9, 2022. Based on industry
reporting, a malicious cyber actor is selling a cross-site scripting (XSS)
exploit kit for the ZCS vulnerability to CVE 2022 30333. A Metasploit module
is also available that creates a RAR file that can be emailed to a ZCS server
to exploit CVE-2022-30333.[8 ] CVE-2022-24682 CVE-2022-24682 is a medium-
severity vulnerability that impacts ZCS webmail clients running releases
before 8.8.15 patch 30 (update 1), which contain a cross-site scripting (XSS)
vulnerability allowing malicious actors to steal session cookie files.
Researchers from Volexity shared this vulnerability on February 3, 2022[9 ],
and Zimbra issued a fix on February 4, 2022.[10 ] CISA added this
vulnerability to the Known Exploited Vulnerabilities Catalog on February 25,
2022. DETECTION METHODS Note: CISA and the MS-ISAC will update this section
with additional IOCs and signatures as further information becomes available.
CISA recommends administrators, especially at organizations that did not
immediately update their ZCS instances upon patch release, to hunt for
malicious activity using the following third-party detection signatures:
Update September 27 , 2022 : Hunt for IOCs including: IP Addresses Note
62.113.255[.]70 New September 27, 2022: Used by cyber actors during August
15-26, 2022 while attempting to exploit CVE-2022-27925 and CVE-2022-37042
185.112.83[.]77 New September 27, 2022: Used by cyber actors during August
15-26, 2022 while attempting to exploit CVE-2022-27925 and CVE-2022-37042
207.148.76[.]235 A Cobalt Strike command and control (C2) domain
209.141.56[.]90 New September 27, 2022 Update August 23 , 2022 : Deploy Snort
signatures to detect malicious activity: alert tcp any any -> any any
(msg:”ZIMBRA: HTTP POST content data ‘.jsp’ file'”; sid:x;
flow:established,to_server; content:”POST”; http_method;
content:”|2f|service|2f|extension|2f|backup|2f|mboximport”; nocase; http_uri;
content:”file|3a|”; nocase; http_client_body; content:”|2e|jsp”;
http_client_body; fast_pattern; classtype:http-content;
reference:cve,2022-30333;) alert tcp any any -> any any (msg:”ZIMBRA: Client
HTTP Header ‘QIHU 360SE'”; sid:x; flow:established,to_server; content:”POST”;
http_method; content:”|2f|service|2f|extension|2f|backup|2f|mboximport”;
nocase; http_uri; content:”QIHU|20|360SE”; nocase; http_header; fast_pattern;
classtype:http-header; reference:cve,2022-30333;) alert tcp any any -> any any
(msg:”ZIMBRA:HTTP GET URI for Zimbra Local Config”; sid:x;
flow:established,to_server;
content:”/public/jsp/runas.jsp?pwd=zim&i;=/opt/zimbra/bin/zmlocalconfig|3a|-s”;
http_uri; classtype:http-uri; reference:cve,2022-30333;) Deploy third-party
YARA rules to detect malicious activity: See Volexity’s Mass Exploitation of
(Un)authenticated Zimbra RCE: CVE-2022-27925 Mitigations CISA and the MS-ISAC
recommend organizations upgrade to the latest ZCS releases as noted on Zimbra
Security – News & Alerts and Zimbra Security Advisories . See Volexity’s Mass
Exploitation of (Un)authenticated Zimbra RCE: CVE-2022-27925 for mitigation
steps. Additionally, CISA and the MS-ISAC recommend organizations apply the
following best practices to reduce risk of compromise: Maintain and test an
incident response plan. Ensure your organization has a vulnerability
management program in place and that it prioritizes patch management and
vulnerability scanning of known exploited vulnerabilities . Note: CISA’s Cyber
Hygiene Services (CyHy) are free to all state, local, tribal, and territorial
(SLTT) organizations, as well as public and private sector critical
infrastructure organizations: cisa.gov/cyber-hygiene-services . Properly
configure and secure internet-facing network devices. Do not expose management
interfaces to the internet. Disable unused or unnecessary network ports and
protocols. Disable/remove unused network services and devices. Adopt zero-
trust principles and architecture , including: Micro-segmenting networks and
functions to limit or block lateral movements. Enforcing phishing-resistant
(MFA) for all users and virtual private network (VPN) connections. Restricting
access to trusted devices and users on the networks. INCIDENT RESPONSE If an
organization’s system has been compromised by active or recently active threat
actors in their environment, CISA and the MS-ISAC recommend the following
initial steps: Collect and review artifacts , such as running
processes/services, unusual authentications, and recent network connections.
Quarantine or take offline potentially affected hosts . Reimage compromised
hosts . Provision new account credentials . Report the compromise to CISA via
CISA’s 24/7 Operations Center (report@cisa.gov or 888-282-0870). SLTT
government entities can also report to the MS-ISAC (SOC@cisecurity.org or
866-787-4722). See the joint CSA from the cybersecurity authorities of
Australia, Canada, New Zealand, the United Kingdom, and the United States on
Technical Approaches to Uncovering and Remediating Malicious Activity for
additional guidance on hunting or investigating a network, and for common
mistakes in incident handling. CISA and the MS-ISAC also encourage government
network administrators to see CISA’s Federal Government Cybersecurity Incident
and Vulnerability Response Playbooks . Although tailored to federal civilian
branch agencies, these playbooks provide detailed operational procedures for
planning and conducting cybersecurity incident and vulnerability response
activities. ACKNOWLEDGEMENTS CISA and the MS-ISAC would like to thank Volexity
and Secureworks for their contributions to this advisory. DISCLAIMER The
information in this report is being provided “as is” for informational
purposes only. CISA and the MS-ISAC do not provide any warranties of any kind
regarding this information. CISA and the MS-ISAC do not endorse any commercial
product or service, including any subjects of analysis. Any reference to
specific commercial products, processes, or services by service mark,
trademark, manufacturer, or otherwise, does not constitute or imply
endorsement, recommendation, or favoring. References [1] CVE-2022-27925 detail
[2] Mass exploitation of (un)authenticated Zimbra RCE: CVE-2022-27925 [3]
CVE-2022-37042 detail [4] Authentication bypass in MailboxImportServlet
vulnerability [5] CVE-2022-30333 detail [6] UnRAR vulnerability exploited in
the wild, likely against Zimbra servers [7] Zimbra Collaboration Kepler 9.0.0
patch 25 GA release [8] Zimbra UnRAR path traversal [9] Operation EmailThief:
Active exploitation of zero-day XSS vulnerability in Zimbra [10] Hotfix
available 5 Feb for zero-day exploit vulnerability in Zimbra 8.8.15 Revisions
August 16, 2022: Initial Version August 22, 2022: Added Snort Signatures
August 23, 2022: Updated Detection Methods Snort Signatures This product is
provided subject to this Notification and this Privacy & Use policy. August 16 2022 10:38:42
AA22-228A: Threat Actors Exploiting Multiple CVEs Against Zimbra Collaboration Suite

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