Malicious PDF — malware analysis report

Static analysis result for SHA-256 b168bc3256db7a5c…

MALICIOUS

PDF

87.7 KB Created: 2021-07-09 12:55:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 406e8436ebdecac96ce82f392b8de544 SHA-1: 1062495c6f8d58d5f23bcafe82aebcbacfc4e1a9 SHA-256: b168bc3256db7a5c133a8eac069373f18e6998b45f22c15ead2f3f89129ddc2d
96 Risk Score

Malware Insights

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

The PDF file contains a large number of embedded URLs pointing to various websites, many of which appear to be compromised WordPress installations. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates the document functions as a link farm, likely for SEO manipulation or to distribute malicious content. The ML classifier also strongly flagged this PDF as malicious.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

Heuristics 5

  • 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=can+you+refreeze+thawed+hot+dogs
    • https://www.sanier.pl/wp-content/plugins/super-forms/uploads/php/files/cai34rqc2anit7k7tj1e9i7tqp/buxeb.pdf
    • https://123kozijnofferte.nl/wp-content/plugins/super-forms/uploads/php/files/01fssjpteif7j61aoiio69si60/94461684854.pdf
    • http://xn--80aantfcaehjbxzf1m.xn--p1ai/userfiles/file/19913325729.pdf
    • http://posekatzahradu.cz/files/file/31147269742.pdf
    • http://www.empresasdelimpeza.info/wp-content/plugins/formcraft/file-upload/server/content/files/160830922230d2---53822933580.pdf
    • http://automotiveenergy.cz/userfiles/file/gegorabaxilosotipoziwe.pdf
    • http://wildpflanzen-planung.de/file/10749067283.pdf
    • http://teamwork-poetschke.com/ckfinder/userfiles/files/xelinupojuzaro.pdf
    • http://penoplex24.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160b861675cd7e---31294871113.pdf
    • http://www.infranetltd.com/wp-content/plugins/formcraft/file-upload/server/content/files/160cf471163d08---gujewopajaxefud.pdf
    • https://www.alongsideasia.com/wp-content/plugins/super-forms/uploads/php/files/ab70bf0f70ff01cc274d89b74a32f01f/30016231284.pdf
    • http://apcmagon.com/userfiles/rojerokis.pdf
    • https://ancoraeducacion.com/images/xojosilojezatusidap.pdf
    • https://nezrenpin.com/calisma2/files/uploads/52753741395.pdf
    • http://bonfiremadigan.com/uploads/fckeditor/file/rasizatixofaw.pdf
    • http://kaufdeinauto.de/wp-content/plugins/formcraft/file-upload/server/content/files/160e1f76518364---72173078629.pdf
    • https://lostsoulsmemorialnj.org/wp-content/plugins/super-forms/uploads/php/files/54910523a1b377b2ecc933c5087cdce3/fumafinarewixu.pdf
    • http://abpaluso.com/upload/file/3894041639.pdf
    • http://falegnameriacastiglione.it/userfiles/files/59705544720.pdf
    • http://aliancegroup.su/wp-content/plugins/formcraft/file-upload/server/content/files/16083647212996---jabawekabenobokidud.pdf
    • https://www.ideaklinikkadikoy.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c11c7dacbcf---64719295241.pdf
    • https://www.stamfordtaxis.com/wp-content/plugins/super-forms/uploads/php/files/5p4n8pvlut817htvtk430rdfki/mebat.pdf
    • https://englewoodgrassfarm.com/wp-content/plugins/super-forms/uploads/php/files/45e2830553ce2e59df5c7a0830381845/88997923549.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_off0000f530.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF530 16792 bytes
font_01_sfnt_off00010d42.bin
d1810580f9c82f37f4128701ab2bb6461d691f890bf8d555e908eb0b1903aa53
pdf-font-stream PDF embedded font (sfnt) at offset 0x10D42 16660 bytes
font_02_sfnt_off00013890.bin
615f00faba88037ad9f20b55d27959beef47858a1432f24bb81f41ec1d8fe512
pdf-font-stream PDF embedded font (sfnt) at offset 0x13890 10888 bytes