Malicious PDF — malware analysis report

Static analysis result for SHA-256 88c4d940766dfd5c…

MALICIOUS

PDF

87.6 KB Created: 2021-07-22 06:28:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: c80410f53520d06d0f886f2eb25e8005 SHA-1: 2b0af94a0684226a420099ea046f4251dcfdd20b SHA-256: 88c4d940766dfd5cf0e287faf43846a5915073f0fe6954ab3b0ce6772f0fd402
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The file is a PDF identified as malicious by ClamAV and an ML classifier. It contains numerous embedded URLs, many pointing to compromised CMS upload directories or disposable hosting, indicating it's designed as a link farm. The primary purpose appears to be directing users to potentially malicious content on external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9912

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://atraba-holding.com/userfiles/file/67271651721.pdf
    • https://hophamthaibinh.com/upload/files/22198847860.pdf
    • http://gostinica-domodedovo.ru/files/17471529436.pdf
    • http://sibservis.com/ckfinder/userfiles/files/lotusatikugeseduzegu.pdf
    • https://viettincapital.vn/upload/files/juwafunilibozeputon.pdf
    • http://wypelnienia.kratex.pl/wp-content/plugins/super-forms/uploads/php/files/cc9664b36e4e5b8a09dc0ba31d81583b/goxiluriduzudituburi.pdf
    • http://www.pianoszimmermann.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1608920e49be21---15449210561.pdf
    • https://iominneapolis.com/wp-content/plugins/super-forms/uploads/php/files/7a9ca3b3f4364b91ddcb649d4a811946/rigomixegefiku.pdf
    • https://legacyltg.com/wp-content/plugins/super-forms/uploads/php/files/976e6e658772c48af53db24354959fda/papokutezilamiwasupax.pdf
    • https://njsolarpower.com/wp-content/plugins/super-forms/uploads/php/files/dbd3a0a2f18295cc819c5094b0bfd65d/63114772639.pdf
    • http://chokmanee.com/userfiles/file/58426472412.pdf
    • http://iamsoldierfit.com/wp-content/plugins/formcraft/file-upload/server/content/files/160922be9440c1---kuvazaxuv.pdf
    • https://inchirierielicopter.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160a090e79c7c4---rulikomazepesijobubog.pdf
    • https://bevelec.com/bevelec/dossierMois/file/36870736993.pdf
    • http://ttworld.hu/uploads/content_files/files/1011358983.pdf
    • http://chiari-web.com/ckfinder/optimist/files/zalumapaxuduzug.pdf
    • https://avis-medical.ma/wp-content/plugins/super-forms/uploads/php/files/d5011df5c1ffb530f59c4c5acf4c14ab/ririmad.pdf
    • https://www.etbsupplies.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ce43f30a139---jedekawavividi.pdf
    • http://archimax.ch/dynamic-images/cms/file/raxunejazepipunet.pdf
    • http://in-dapt.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609447b558848---rerig.pdf
    • https://dvg.asia/ckfinder/uploadfiles/files/69791735714.pdf
    • https://ebooksweb.net/files/file/jideradewo.pdf
    • https://alkhairi.co.uk/wp-content/plugins/super-forms/uploads/php/files/44289e6e236fabf85b3f0449f5086b16/50232956947.pdf
    • http://am-assets.com/aom/magnolia/userfiles/file/bifexabuxaradurejujabe.pdf
    • https://cruiseship.cruises/wp-content/plugins/super-forms/uploads/php/files/pd9bnrp898cga47pujan6imeln/tigebalevularenudebekane.pdf
    • https://houstoncoinshow.org/FCKeditor/file/74419487056.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/S30rS-6n6vg/uplcv?utm_term=poison+rock+and+roll+all+nite
    • 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_off0000f3ac.bin
2a7eab04557b058249f4d590f8c250f0a70777e242602decf10319a1fabd2900
pdf-font-stream PDF embedded font (sfnt) at offset 0xF3AC 17332 bytes
font_01_sfnt_off00012071.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x12071 16792 bytes
font_02_sfnt_off00013888.bin
257f030d6a08fa6a676b8193e0d43117bbf32267ce8541691f571a01ff3ea5af
pdf-font-stream PDF embedded font (sfnt) at offset 0x13888 10456 bytes