Malicious PDF — malware analysis report

Static analysis result for SHA-256 13bcc11439da8bd6…

MALICIOUS

PDF

275.1 KB Created: 2010-04-21 00:46:53 +08:00
MD5: a02f67c1ec2068138ee82f9993ce93ae SHA-1: a3f8ca1c6fa38cfe9e3a806da716619217bea745 SHA-256: 13bcc11439da8bd67b901346742657d24e45dd7f4526eb24f24741f3f638b8bb
262 Risk Score

Malware Insights

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

The PDF contains embedded JavaScript that is flagged as an exploit cluster, including an eval() call. This JavaScript is likely responsible for downloading and executing a secondary payload. The ML classifier and ClamAV detection strongly indicate malicious intent. No specific family could be identified.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9074

Heuristics 11

  • 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: Pdf.Exploit.Agent-35956 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-35956
  • RichMedia (Flash) high PDF_RICHMEDIA
    PDF contains /RichMedia (Adobe Flash) which is a historic exploit vector (matched inside decoded stream)
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • 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. (matched inside decoded stream)
  • 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. (matched inside decoded stream)
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload (matched inside decoded stream)
  • PDF paints image(s) but contains no text operators info PDF_IMAGE_ONLY_LURE
    PDF has 2 image XObject(s) and the content stream contains no text-emitting operators (BT/ET, Tj, TJ, ', ") in either raw bytes or decompressed streams — this is the screenshot-as-PDF pattern used to bypass text-based scanners and to deliver instructions purely through rendered pixels. It is informational unless paired with invisible links or risky URI context.
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/photoshop/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/tiff/1.0/
    • http://ns.adobe.com/exif/1.0/
    • http://ns.adobe.com/pdf/1.3/

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_012_off000434ad.js
a8e9a031915fc297bf10a6ec84576b5b55a9de0263ee4db0e5604573a17731a2		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x434AD 9494 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).
objstm_0015_00.bin
0bea2f3f6742827130b057b701b07bdcb51c89b49c3509980c44a0392473f8fb		 pdf-objstm-decoded PDF /ObjStm 15 0 obj (inflated) 888 bytes
objstm_0043_00.bin
34adfa579a1db11b7419ab08cf86866f8443676d947c2196bbfc0c97edf23a79		 pdf-objstm-decoded PDF /ObjStm 43 0 obj (inflated) 32 bytes
objstm_0048_00.bin
950f1bd1fbb167275a774acfa49d579367ba1b22fa7f54188161bf0439584559		 pdf-objstm-decoded PDF /ObjStm 48 0 obj (inflated) 32 bytes

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