Malicious PDF — malware analysis report

Static analysis result for SHA-256 d042c537d8bb1bc2…

MALICIOUS

PDF

97.4 KB Created: 2021-08-16 23:12:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 7fe995a54b6b634c9dcc05cf36762d06 SHA-1: 7e6f512043ef35f7ab7e89e86fd805f1d25a77ef SHA-256: d042c537d8bb1bc27c33273b0b06af5a085ef6be6f7dca705363da1ea6af5273
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was flagged by multiple heuristics and a machine learning classifier as malicious, with ClamAV identifying it as a phishing trojan. It contains numerous links to external websites, many hosted on compromised CMS platforms or disposable domains, suggesting a phishing or malware distribution campaign. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, but the presence of external links and the overall detection profile strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9983

Heuristics 6

  • 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 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://pistant.ru/uplcv?utm_term=information+security+cyber+law+lecture+notes
    • http://fteq.ru/files/file/41255828840.pdf
    • http://www.driftime.ee/wp-content/plugins/formcraft/file-upload/server/content/files/160aa4354d2c07---82577822195.pdf
    • https://vmwarts.com/ecovic/file/53879359355.pdf
    • https://monarchwinemerchants.com/wp-content/plugins/super-forms/uploads/php/files/c46be8d3d25d0ba3aaddc76d91b195c3/bomonuxiditisefopabomizor.pdf
    • https://www.colegiodesafio.net/home/wp-content/plugins/formcraft/file-upload/server/content/files/16075fe3176c18---82351881030.pdf
    • http://sz-nuoyi.com/Upload/file/2021072810375976975.pdf
    • https://www.simcoerecovery.net/wp-content/plugins/super-forms/uploads/php/files/t3l4j58q423st266qhbpcloh2f/nijiwogafi.pdf
    • https://sdhouse.info/ckfinder/userfiles/files/71604542698.pdf
    • https://www.lowdoc-loans.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160a92a08e565c---40798604247.pdf
    • https://olgunbey.com/upload/ckfinder/files/88937968920.pdf
    • https://htfcompact.com/wp-content/plugins/super-forms/uploads/php/files/ede4afee48f4d55216cf87142aa7b782/21442417929.pdf
    • http://phongkhamthienhoa.vn/images/files/61066342165.pdf
    • http://kapelski.pl/userfiles/file/pekelifazagu.pdf
    • https://couvreur-hautdoubs.fr/internet_new/images_et_fichiers//file/63400448917.pdf
    • https://www.sacproblemleri.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c308320caec---wunawikodelepasul.pdf
    • http://ebiocell.com/uploadfile/file///2021071304515918.pdf
    • http://zgkimsteszew.pl/img/upload/files/xoxujifebilesijudelixofi.pdf
    • http://yuanjen.com/ckfinder/userfiles/files/tuwizofixiwavumoje.pdf
    • http://www.johnknox.ch/wp-content/plugins/formcraft/file-upload/server/content/files/160c9ad54a3059---luwupunegoj.pdf
    • http://syuncyoku.jp/upload/file/2022616989.pdf
    • http://hissekurban.com/resimler/files/12203216819.pdf
    • http://eakqshop.com/ckfinder/images_store/files/fitufaf.pdf
    • http://inlikeflintlogistics.com/wp-content/plugins/formcraft/file-upload/server/content/files/160df8d105e9d3---jenapo.pdf
    • http://czechnews.cz/userfiles/files/pikikusujataxet.pdf
    • http://kadernictvo-svetlana.sk/editor_uploads/system/files/27347676830.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_off00011641.bin
2a93646dfa8daa34d28ab0f20d374ccbf5b68a2f38cd55ca92ac1980bdefeb54
pdf-font-stream PDF embedded font (sfnt) at offset 0x11641 10888 bytes
font_01_sfnt_off00012f89.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x12F89 16792 bytes
font_02_sfnt_off0001479b.bin
74fcadf466fb53e96a710fe0528412363cce34f807d3dfb1a9b94a4b99f52abc
pdf-font-stream PDF embedded font (sfnt) at offset 0x1479B 17852 bytes