Malicious PDF — malware analysis report

Static analysis result for SHA-256 7d08a0d0d0d05073…

MALICIOUS

PDF

82.2 KB Created: 2021-02-13 10:30:36 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: ce760df6f9c2f684e3e466e3a2644868 SHA-1: e611c1bbdba4526fd5dc72866d23911cf03baa85 SHA-256: 7d08a0d0d0d05073e22109f73a98b4d971f6f386d8143f35695db73e1ef2a7f2
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF contains numerous external links, with a critical heuristic firing for a 'PDF_SEO_LINK_FARM' indicating a large number of links to potentially malicious sites. One such link, http://ezfix.asia/729913796377z2ur.pdf, is identified as a critical indicator. The ML classifier and ClamAV also flagged this PDF as malicious, specifically as a phishing trojan. The document body, though heavily obfuscated, suggests a pretext of a 'letter of reference for student athlete' to mask its malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 5

  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://jacksth.ru/wix?keyword=letter+of+reference+for+student+athlete
    • http://ezfix.asia/729913796377z2ur.pdf
    • https://cdn.sqhk.co/luluzefob/YFShUZE/mega_mall_story_2_floor_compatibility.pdf
    • http://myyshooop224.site/fuxubogeidgbo.pdf
    • https://cdn.sqhk.co/talexadu/aIfEHW5/zombie_survival_frontier_gun_shooting_games.pdf
    • https://bivufinemena.weebly.com/uploads/1/3/1/3/131380184/fuzivesipezux.pdf
    • http://heretythere.site/fawideledapusetipoldcsb.pdf
    • http://romeoplanet.club/figuvukigavasopuvone60c43.pdf
    • http://samo-katim.ru/15776026132dsdn7.pdf
    • https://wunaramalus.weebly.com/uploads/1/3/4/5/134576193/5478984.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://www.daltonmaag.com/
    • https://s3.amazonaws.com/fifuto/23118684528.pdf
    • https://s3.amazonaws.com/vudivuzakal/fipetajajif.pdf
    • https://s3.amazonaws.com/zunewidimem/wigogepeberitipapikonidoj.pdf
    • https://s3.amazonaws.com/fajetufekejo/pigoledo.pdf
    • https://s3.amazonaws.com/dojivewobasuval/16007164106.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://scripts.sil.org/OFL

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f8d5.bin
b59322b025cbd5dc60e099744753069f24263ca48b37c2ebad2a5dd7e3e02cd9
pdf-font-stream PDF embedded font (sfnt) at offset 0xF8D5 4884 bytes
font_01_sfnt_off00010965.bin
28fafaa8f2ea95bc49dd10c19a6152de8b7e0d2319ab48f82c26fdcd65d1e62a
pdf-font-stream PDF embedded font (sfnt) at offset 0x10965 10548 bytes
font_02_sfnt_off00012d66.bin
b50a2106bf82917db0cd3cf88f63c5e8cc3298b343ace5cffc591b35df33d24c
pdf-font-stream PDF embedded font (sfnt) at offset 0x12D66 4324 bytes