cbcvebase.
CVE-2020-8209
published 2020-08-17

CVE-2020-8209: Improper access control in Citrix XenMobile Server 10.12 before RP2, Citrix XenMobile Server 10.11 before RP4, Citrix XenMobile Server 10.10 before RP6 and…

PriorityP183high7.5CVSS 3.1
AVNACLPRNUINSUCHINAN
ITWEXPLOITVulnCheck KEV
Exploited in the wild
EPSS
48.66%
98.7th percentile
Improper access control in Citrix XenMobile Server 10.12 before RP2, Citrix XenMobile Server 10.11 before RP4, Citrix XenMobile Server 10.10 before RP6 and Citrix XenMobile Server before 10.9 RP5 and leads to the ability to read arbitrary files.

Affected

8 ranges
VendorProductVersion rangeFixed in
citrixcitrix_endpoint_management
citrixxenmobile
citrixxenmobile_server<= 10.8.0
citrixxenmobile_server
citrixxenmobile_server
citrixxenmobile_server
citrixxenmobile_server
citrixxenserver

Detection & IOCsextracted from sources · hover to see the quote

url/jsp/help-sb-download.jsp?sbFileName=../../../etc/passwd
path/jsp/help-sb-download.jsp
snort
alert http any any -> [$HOME_NET,$HTTP_SERVERS] any (msg:"ET WEB_SPECIFIC_APPS Citrix XenMobile Server Directory Traversal Attempt Inbound (CVE-2020-8209)"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"?sbFileName=../"; fast_pattern; reference:url,github.com/B1anda0/CVE-2020-8209/blob/main/CVE-2020-8209.py; reference:cve,2020-8209; classtype:attempted-admin; sid:2031221; rev:1; metadata:created_at 2020_11_19, cve CVE_2020_8209, deployment Perimeter, deployment Internal, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_11_19, mitre_tactic_id TA0007, mitre_tactic_name Discovery, mitre_technique_id T1083, mitre_technique_name File_And_Directory_Discovery; target:dest_ip;)
  • Exploit requests use HTTP GET to /jsp/help-sb-download.jsp with the query parameter sbFileName containing directory traversal sequences (e.g., ../../../etc/passwd). Match on URI containing '?sbFileName=../'.
  • Successful exploitation returns an HTTP response with headers containing 'fileDownload=true', 'application/octet-stream', and 'attachment;' simultaneously — use these as confirmation matchers.
  • Response body containing the regex 'root:.*:0:0:' confirms successful /etc/passwd file read via LFI.
  • Nuclei template targets max-request: 1 GET request; the vulnerability is unauthenticated (PR:N) and network-reachable (AV:N), so no authentication bypass is needed prior to exploitation.
  • ·Affected versions are Citrix XenMobile Server 10.12 before RP2, 10.11 before RP4, 10.10 before RP6, and versions before 10.9 RP5. Detection rules should be scoped to these versions where version fingerprinting is possible.
  • ·The Snort/ET rule (sid:2031221) is tagged for both Perimeter and Internal deployment, indicating the traversal attempt should be monitored on both network boundaries.
  • ·EPSS score of 0.93007 (99.784th percentile) indicates extremely high real-world exploitation probability; prioritize detection and patching accordingly.

CVSS provenance

nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
nvdv2.05.0MEDIUMAV:N/AC:L/Au:N/C:P/I:N/A:N
vulncheck7.5HIGH
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