Malicious PDF — malware analysis report

Static analysis result for SHA-256 a490436c24408cf0…

MALICIOUS

PDF

167.5 KB Created: 2008-05-18 16:13:09 +08:00 Authoring application: Acrobat 编辑器 8.0 (via Adobe Acrobat 8.0)
MD5: d83815564ca0aa27c4a45f32a5eaa436 SHA-1: 538be7120842bac80220ba01fe2bec39866ba482 SHA-256: a490436c24408cf0fa85243603a13561c15b9757cb1fb6374cca63b05e149f86
170 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.001 Malicious Link

This PDF document contains embedded JavaScript and triggers a critical heuristic for CVE-2007-5659 (Collab.collectEmailInfo). The ML classifier also flagged it as malicious with high confidence. The embedded JavaScript stream, named 'javascript_obj0114_000.js', is likely responsible for the malicious activity, potentially downloading and executing a second-stage payload. The presence of XFA forms and embedded files further suggests a complex malicious document structure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 10

  • Collab.collectEmailInfo — CVE-2007-5659 critical CVE exact CVE_2007_5659
    PDF JavaScript calls Collab.collectEmailInfo — CVE-2007-5659 is a buffer overflow in Adobe Reader triggered by a long argument or heap-sprayed message field passed to Collab.collectEmailInfo(). Part of a series of Acrobat JS API exploits. (matched in decompressed stream)
  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits (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.
  • 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.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • XFA form low PDF_XFA
    PDF uses XML Forms Architecture — can contain script logic
  • 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.
  • PDF differential parser failed info PDF_DIFFERENTIAL_PARSE_FAILED
    The cross-check parser (pdfminer.six) failed on this file: PDF differential parser failed: PermissionError. Static heuristics still ran and any of their findings above are valid; only the differential cross-check signal is missing.
  • 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/xap/1.0/mm/
    • http://ns.adobe.com/pdf/1.3/
    • http://www.w3.org/1999/xhtml
    • http://www.xfa.org/schema/xfa-data/1.0/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
temp.JPG
0cbf810052e0b9800129459208ec15487bee990832eef4fd5669cd0378aaf2de		 pdf-embedded-file PDF EmbeddedFile object 116 at offset 0x16CD8 72845 bytes
javascript_obj0114_000.js
3dca895cad1feef42f0890d9bc8b7c24ceb7dd0a1399c83ee2870e29c619d9e8		 pdf-javascript-stream PDF /JS object 114 at offset 0x1647B 4505 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 16 eval/decoder/string-building token(s).

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