Malicious PDF — malware analysis report

Static analysis result for SHA-256 722e81c54cc11e7b…

MALICIOUS

PDF

195.4 KB Created: 2010-07-26 16:38:32 Authoring application: Microsoft® Office Word 2007
MD5: c8170125653f94fe474ab0a434cf2920 SHA-1: 3d4f76b396082597fccd4e0be43aec7c04312d8a SHA-256: 722e81c54cc11e7bbbb7cf68c9a3c0ab98a0ddcd241b63d1754eabf4ea3a65e1
310 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

This PDF file contains embedded JavaScript that utilizes the unescape() function and exploits CVE-2008-2992 and potentially CVE-2023-26369. The JavaScript is heavily obfuscated but is flagged by multiple heuristics as an exploit cluster and is associated with ClamAV detection 'Js.Exploit.Shellcode-18'. The primary function of the embedded JavaScript is to download and execute a second-stage payload, indicated by the exploit cluster and shellcode detection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9969

Heuristics 9

  • util.printf — CVE-2008-2992 critical CVE exact CVE_2008_2992
    PDF JavaScript calls util.printf() — CVE-2008-2992 is a stack buffer overflow in Adobe Reader triggered by a long format-specifier argument. Widely exploited in the wild after disclosure.
  • TrueType bitmap font + active content — CVE-2023-26369 related high CVE related PDF_CVE_2023_26369_RELATED
    PDF embeds a TrueType font with bitmap tables (EBDT/sbix/CBDT) alongside exploit delivery indicators — CVE-2023-26369 exploits the sfac_GetSbitBitmap function in Adobe's libCoolType for arbitrary code execution. This CVE was actively exploited in the wild, but this rule does not validate the malformed EBLC/EBDT primitive.
  • PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTER
    PDF combines an executable JavaScript/action surface with exploit staging indicators such as eval/unescape/fromCharCode, XFA script content, or a related CVE pattern. Benign form JavaScript remains low-severity, but this correlated cluster is high-confidence malicious behavior.
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits
  • JavaScript action low PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.color.org
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://ns.adobe.com/pdf/1.3/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://www.aiim.org/pdfa/ns/id/
    • http://www.microsoft.com/typography/ctfontshttp://fontfabrik.comYou
    • http://www.microsoft.com/typography/fonts/default.aspx
    • http://crl.microsoft.com/pki/crl/products/CSPCA.crl0H
    • http://www.microsoft.com/pki/certs/CSPCA.crt0
    • http://crl.microsoft.com/pki/crl/products/tspca.crl0H
    • http://www.microsoft.com/pki/certs/tspca.crt0
    • http://www.microsoft.com/typography

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0057_000.js
ea139b942ead4119a0729e527c1582a1df531046252c375453a2a95d30c2b04a		 pdf-javascript-stream PDF /JS object 57 at offset 0x2F15B 5823 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).
javascript_obj0057_001.js
89b7c9d4bc7ae1acb8478a5d2015e8780e5ef7bdf7977bcbc1f03874dc263fcb		 pdf-javascript-stream PDF /JS object 57 at offset 0x2F190 7179 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).
stream_002_off00001f51.bin
1b3d79e17f65a53e314ece9e01b54b298fb91c87ba1abec996f3aa8ae086593b		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x1F51 190988 bytes
combined_document_js_000.js
171edc156bec22bb93dd162a6daa642cebc4dfde335b486cbedf013985abb7ec		 deobfuscated-js combined document JavaScript streams at offset 0x2F15B 13003 bytes
Detection
ClamAV: Js.Exploit.Shellcode-18
Obfuscation or payload: likely
Carved artifact contains 6 eval/decoder/string-building token(s).

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