Malicious PDF — malware analysis report

Static analysis result for SHA-256 ac8c227da40f6a56…

MALICIOUS

PDF

81.5 KB Created: 2021-09-22 09:37:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 7934e507a89cfd027ed76f653913a49c SHA-1: 679a4450c3a5d44295429e9de8a02195ac98d6a8 SHA-256: ac8c227da40f6a56f774ba63fc4b326b53698b5aeff0b8c5172d1a63646cc34d
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains multiple links to external websites, with one heuristic specifically identifying a link to a compromised WordPress upload storage. ClamAV detected this file as 'Pdf.Phishing.Trojan', and the ML classifier also flagged it as malicious. The presence of numerous external links suggests the document's primary purpose is to redirect the user to potentially malicious content, aligning with phishing or malware distribution tactics.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • PDF link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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 http://tvsatkrosno.pl/userfiles/file/41770446317.pdf
    • http://www.absolutecateringla.com/wp-content/plugins/formcraft/file-upload/server/content/files/16132a5552b357---wibet.pdf
    • http://www.sunaryem.com.tr/wp-content/plugins/super-forms/uploads/php/files/97kt2d7pu65cq0qndgi44pttk7/13930163387.pdf
    • http://yomamasushitogo.com/uploads/files/29584511417.pdf
    • http://condominiobrisasdelnorte.com/userfiles/file/81336457190.pdf
    • https://dauglita.lt/components/com_mijoshop/opencart/image/data/files/47404805801.pdf
    • https://kokomanis.com/contents/files/9174610461.pdf
    • http://www.kissdocs.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/161482ea20293e---bidudekelifanig.pdf
    • http://mexvp.com/ckfinder/userfiles/files/fexepugogetamaxovaw.pdf
    • https://detectiveoffice.net/userfiles/file/40786117527.pdf
    • https://rh4-h1tapi-turbo.com/contents/files/69884724978.pdf
    • https://chongtham68.com/app/webroot/uploads/files/15949840735.pdf
    • http://bukvoznaika.ru/ckfinder/userfiles/files/49797356766.pdf
    • https://hometutorsdelhi.com/userfiles/files/86952494321.pdf
    • https://onlineadda.net/ckfinder/userfiles/files/tekejuj.pdf
    • http://asustainable.com/global/file/zimigowim.pdf
    • https://www.physioaktivkramer.de/wp-content/plugins/formcraft/file-upload/server/content/files/161384b10708a5---61588398737.pdf
    • https://cantellodetersiviprofessionali.it/uploads/file/zuzateze.pdf
    • http://lev-steklo.ru/userfiles/file/74556145013.pdf
    • http://noahmission.org/dataroom/file/79525012531.pdf
    • https://ikuseikyokai.jp/ckmedia/files/71167862106.pdf
    • http://teedinmaesai.com/user_img/file/31734875682.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/PmAiG5ZyT-k/uplcv?utm_term=present+and+past+participles+exercises+pdf
    • 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_off0000d673.bin
e50e8f12a68ff47e5bce93efbd089e29c38f8c3d22b3c10b641ca3545f2b70de
pdf-font-stream PDF embedded font (sfnt) at offset 0xD673 19016 bytes
font_01_sfnt_off00010792.bin
04e9e593ac4efba7d3e96f42dcc383bfee81814402f700ddd0ec95f394374e42
pdf-font-stream PDF embedded font (sfnt) at offset 0x10792 10596 bytes
font_02_sfnt_off00011fe9.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x11FE9 16792 bytes