Malicious PDF — malware analysis report

Static analysis result for SHA-256 5639cf309375ae37…

MALICIOUS

PDF

79.2 KB Created: 2021-07-19 08:21:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 852faf892fdac6cde35edc8dca385bda SHA-1: 0886f964c97895d30cd56d7aa253c0ec16541c58 SHA-256: 5639cf309375ae37f68b9da9f5cbbcf0dd0f00414a315de2734bcae66895b0d0
156 Risk Score

Malware Insights

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

This PDF file was identified as malicious by ML classifiers and ClamAV, indicating a phishing or trojan threat. It functions as a link farm, containing numerous URLs pointing to compromised CMS uploads and disposable hosting, likely intended to redirect users to malicious content. The document body is heavily obfuscated and unreadable, providing no direct clues to its specific purpose beyond the heuristic findings.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • 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.
  • 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 https://ddriu.hu/wp-content/plugins/super-forms/uploads/php/files/238396f898382b1170cb52f1fc43fd11/25798227940.pdf
    • http://datev.hu/ckfinder/userfiles/files/sivirubosokujefub.pdf
    • https://www.helpforbusymums.com/wp-content/plugins/super-forms/uploads/php/files/8ec75c61c2b991e9a15aea2d0b2c8345/rivowumogadukematodatonu.pdf
    • https://ecobox.eng.br/wp-content/plugins/super-forms/uploads/php/files/biotuvi7fsrtham9j5m510ksf5/ponezene.pdf
    • https://totalyoumovement.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c8e9345c1ec---fawunidig.pdf
    • https://nhanloc.net/userfiles/file/72789253210.pdf
    • http://hieuchuan.com/upload/files/46565248086.pdf
    • http://donkaew-furniture.com/ckfinder/userfiles/files/viduvozekupamedurose.pdf
    • http://www.investing-in-women.com/wp-content/plugins/formcraft/file-upload/server/content/files/160aa6b217f70c---fuxolubafewituwod.pdf
    • http://kotolantopeni.cz/file/75056134365.pdf
    • http://sehs67.com/clients/e/e0/e078d4d0076166a7bb489ca3b3a583ab/File/tobavobimajalas.pdf
    • http://canadanur.com/resimler/files/rudojefate.pdf
    • https://arerp.kr/data/file///vewewakigaxevowuzula.pdf
    • https://www.dyna-tech.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1609491a75eae2---83790299618.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/3CAf4wW3hvY/uplcv?utm_term=fraction+solution+with+answer
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d3f5.bin
7f817c79c8a67fb9fa511da1b6262ede3be7f2f9ffe64d6e477841ab93049ebb		 pdf-font-stream PDF embedded font (sfnt) at offset 0xD3F5 10492 bytes
font_01_sfnt_off0000ebd3.bin
2572b3da0f7280f52b47a753fbed8156ad5a72cfdcb2b2ef4f62f85a7dae8129		 pdf-font-stream PDF embedded font (sfnt) at offset 0xEBD3 17032 bytes
font_02_sfnt_off0001185e.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0x1185E 16792 bytes

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