Malicious PDF — malware analysis report

Static analysis result for SHA-256 55aec4b90f0b3ff6…

MALICIOUS

PDF

81.1 KB Created: 2021-09-14 11:49:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 36e79c0ffcf4f1ec6b30b6358bdce777 SHA-1: bed42019e9665e4d4569dfe51c33c47eb8b3b859 SHA-256: 55aec4b90f0b3ff65e6197acd467c773cfea05896416e38848719087a58d989f
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous external links, many pointing to compromised CMS uploads or disposable hosting, suggesting a link farm used for phishing or malware distribution. The presence of embedded URLs and the PDF structure itself are indicative of a malicious document, likely delivered via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://medvor.ru/uplcv?utm_term=android+contacts+extension PDF link annotation
    • https://nusantarabet4d1.com/contents/files/sukijegedibaxu.pdfIn PDF document text
    • https://everywheregenes.com/uploadfile/qu26_qu106_com/files/69649158775.pdfIn PDF document text
    • http://gyuco.com/uploadfile/files/20210913_225107.pdfIn PDF document text
    • https://www.die-umzugsfabrik.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613de91292d10---kofimalokoru.pdfIn PDF document text
    • http://sspvjd.com/FileData/ckfinder/files/20210912_34F7BBF8C0C49A1B.pdfIn PDF document text
    • https://hetodon.com/fckeditorfiles/file/99717040836.pdfIn PDF document text
    • http://odra.cycling-recycling.eu/imgturysta/files/lofot.pdfIn PDF document text
    • http://clear-es.net/yamituki-n/uploads/files/soladafute.pdfIn PDF document text
    • http://achilleferolla.it/userfiles/files/ronukemilejajifadabud.pdfIn PDF document text
    • http://nikolalepojevic5.com/multimedia/file/tenixem.pdfIn PDF document text
    • http://bon-mar.com/fck_user_files/file/verojisu.pdfIn PDF document text
    • https://glycocalyx.nl/userfiles/image/file/zalapikogofixigolitofig.pdfIn PDF document text
    • https://laundrybyconrads.com/nbloom/fckuploads/file/sinegunidimimajakoteneru.pdfIn PDF document text
    • https://noithatkuongthinh.com/uploads/files/18221122414.pdfIn PDF document text
    • https://copperscraphandlers.com/ckfinder/userfiles/files/sewoxi.pdfIn PDF document text
    • https://techson-cctv.com/upload/file/serixazovazexigubumi.pdfIn PDF document text
    • http://szmchem.com/userfiles/file/pewexonugopupusunoruta.pdfIn PDF document text
    • http://tractortools.cz/ckfinder/userfiles/files/20200514440.pdfIn PDF document text
    • https://asiastudy.in/ckfinder/userfiles/files/47656208091.pdfIn PDF document text
    • http://behtarinekhodetbash.com/files/files/sudikimomilifutumujo.pdfIn PDF document text
    • https://austdoorcaocap.com/upload/files/gibelegizixinitulapi.pdfIn PDF document text
    • http://www.scmphotography.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/161374090243d4---89203986546.pdfIn PDF document text
    • https://www.verpoort-bouw.be/wp-content/plugins/formcraft/file-upload/server/content/files/161357cc016430---7657321137.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d7cd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD7CD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000efdf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFDF 18376 bytes
SHA-256: 452041193821bebe8b7d6899c337118dcd75ae054f7969907d47973f84c0efac
font_02_sfnt_off00011ee5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11EE5 10400 bytes
SHA-256: ecaee1e1330c50f277c6e7cdc32f4f1e300dfc13b1032d17c80f32797b5463f8